Time Enough for Love



Time Enough For Love is a Speculative Fiction novel by Robert A. Heinlein, first published in 1973, which fits into his Future History mythology. It is conceptually a sequel to Methuselahs Children and was followed by The Number of the Beast.

Lazarus Long is the oldest living human being by well over a thousand years, thanks to a remarkable genetic heritage and the technology of human rejuvenation. But even a semi-immortal, ornery coot of a man can grow tired of life, and it's long been established in a galactic society of extraordinarily long-lived humans that the right to end one's life when one chooses is as sacred as anything gets.

However, Ira Weatheral, the chairman of the Howard Foundation, disagrees, believing that Lazarus' unique store of human wisdom is worth any cost to save. Lazarus makes a deal with him: he will share his life story from start to finish. In the time that it takes him to do so, Ira has to come up with something new for him to experience. If he cannot, Ira must agree to let Lazarus die peacefully. Thus begins a kind of reverse-Scheherezade Gambit and a Framing Device for an exploration of vast swathes of Heinlein's Future History universe from the point of view of this near-mythological figure.

After Lazarus' rejuvenation, the novel abruptly changes tone and becomes a Time Travel adventure, as this is among the various suggestions that his friends come up with for things that he might do. Given the vastness of human history to choose from, he elects to visit his own childhood family in Kansas City, Missouri. But a slight miscalculation or two might well end the career of this interstellar traveler for good.

Provides Examples Of:
""A 'critic' is a man who creates nothing and thereby feels qualified to judge the work of creative men. There is logic in this; he is unbiased — he hates all creative people equally." "
 * Author Appeal: Since it's a Heinlein book, it's all over the place. Nudism, polyamory, libertarian politics...
 * Author Avatar: Lazarus, in many ways. He's unquestionably an outlet for vast amounts of opining by Heinlein on a variety of subjects.
 * Author Filibuster: Heinlein takes a twenty page break from the story in order to go on a lengthy discussion of genetics which only has a moment of fleeting relevance in the plot.
 * Automaton Horses:
 * Averted -- The genetically engineered "mules" that Lazarus employs on New Beginnings are intelligent enough to tell you when they need food, water, etc. Some are smart enough to be people in their own right, like Buck, and are mourned as people when they die.
 * Discussed -- After Lazarus arrives in 1916, he assists a doctor on the road who is driving one of those "new-fangled" automobiles. The doctor complains that a good horse can be counted on to get itself home without any help from its rider; he misses catching naps while he travels.
 * Badass Grandpa: Lazarus himself, as well as his grandfather Ira Johnson. At seventy, we're told, he can hold an anvil at arm's length. By the horn.
 * Become a Real Boy: See Pinocchio Syndrome. Lazarus is careful to caution Minerva that the actual experience of waking up in a human body is likely to be highly traumatic at first.
 * Beware the Honest Ones: Long comments that "business" politicians are usually honest (in the sense that they stay bought) whereas "reform" politicians tend to be stupidly dishonest, because they are capable of doing literally anything that they believe is in the best interests of the "People."
 * Bindle Stick: Long has one packed for him in 1916 by a kindly doctor's wife, though he re-packs it soon afterward, as it's a liability on the road to look like a "bindle stiff".
 * Bi the Way: In Lazarus' future, among Howards at least, people are open to sex in just about any configuration, although most people still have a preference one way or the other. Lazarus himself claims to be prejudiced towards heterosexuality thanks to his "Bible Belt upbringing", but acknowledges that such emotions are irrational. Later novels in the series Retcon his sexuality to the extent that he claims to have had sex with Andrew Libby while embarked on the "New Frontiers", and "misses" Libby as a male to that extent.
 * Blasting It Out of Their Hands: Done by Dora to a would-be pioneer bandit.
 * Brilliant but Lazy: Lazarus tells Ira the story of "The Man Who Was Too Lazy to Fail": one David Lamb, who went to Annapolis because it was easier than farming, and memorized mathematical tables because it was the easiest way of handling the hazing from the upperclassmen - and that's just for starters. Lazarus implies that his laziness was part and parcel of his brilliance, causing him to become more efficient to avoid unnecessary work. Ira also ventures the opinion that David Lamb was a pseudonym of Lazarus', but historical records fail to corroborate either version of the story.
 * Brother-Sister Incest:
 * Thanks to the cover story that Ira Johnson unknowingly bestows upon Lazarus, Maureen initially believes that she is bedding her half-brother. It is strongly implied that she wouldn't have cared either way; and she is unfazed to find out the truth in The Number of the Beast.
 * Lazarus sleeping with Laz/Lor can be considered this, along with Screw Yourself and Parental Incest, depending on your point of view.
 * Bury Me Not on the Lone Prairie/Burial in Space: Long tries to give Andrew Libby the cremation he requested, by letting him burn up de-orbiting into Earth. Problem is, he dies on the other side of the galaxy, but thankfully corpses keep well in space. Long sets up the body in an orbit around the planet where Libby died, knowing he can always come back later when it's possible to get to Earth and retrieve the body. Oddly enough someone steals it before he can come back, and even odder it turns out to be Lazarus himself. (Time Travel is fun like that). However, in The Number of the Beast, we discover that he steals Libby's corpse a second time so they can recapture his DNA and memories and clone him, this time as a woman, since Libby very helpfully provided XXY sex chromosomes.
 * Caustic Critic: Discussed:

""There is only one way to console a widow. But remember the risk.""
 * Combat Pragmatist: Lazarus regards anyone who doesn't fight to win as stupid. And dead, if he goes up against Lazarus. It's certainly one of the ways he's managed to live so long, by being prepared to fight -- and fight dirty -- at a moment's notice. When he enlists in World War One, his knowledge of vicious fighting styles gets him a reputation as a mercenary on the lam from the French Foreign Legion.
 * Comforting the Widow: From The Notebooks Of Lazarus Long

""I told you my memory was playing tricks. I've used Andy Libby's hypno-encyclopedic techniques - and they're good - and also learned tier storage for memory I didn't need every day, with keying words to let a tier cascade when I did need it, like a computer, and I have had my brain washed of useless memories several times in order to clear those file drawers for new data - and still it's no good. Half the time I can't remember where I put the book I was reading the night before, then waste a morning looking for it - before I remember that that book was one I was reading a century ago.""
 * Computer Voice: Minerva has two voice address modes -- an "impersonal" mode, where she is monotone and robotic, and a "personal" mode, where she sounds completely human. She uses the latter more frequently with Lazarus as he grows more comfortable with her.
 * Contemptible Cover: Most paperback editions, including the image above.
 * Cool Old Guy: Ira Johnson, patriarch of his family, and the greatest single influence on the young Woodrow Wilson Smith, who of course grew up to become Lazarus.
 * Coup De Grace: Administered by Lazarus to an injured, would-be pioneer bandit --.
 * Covers Always Lie:
 * The back cover blurb of the novel implies a My Own Grampa plot where none such occurs. On the other hand, his cover story does result in him being taken for his own distant uncle.
 * It also provides incorrect start and end dates for Lazarus' life: 1916 rather than 1912 for his birth, and 4272 for his death, which is not only wrong -- the Tertius segment is explicitly set in 4292 -- but almost spoils the ending.
 * Defictionalization: The Notebooks of Lazarus Long, a fictional compilation of Lazarus' quotable sayings presented in interludes of the novel, has itself been published as a separate novel.
 * Determined Homesteader: Lazarus
 * Determined Homesteader's Wife: Dora
 * Did Not Do the Research: In-Universe, Lazarus fails to anticipate the precise date that the United States gets into World War One because he didn't bother to study anything that happened prior to his intended arrival. As such, he relies only on vague childhood memories of "the guns of August" and is caught with his pants down by the actual event. This leads directly to him screwing up his relationship with his grandfather, then enlisting in order to fix it, and subsequently.
 * Dismotivation: See Brilliant but Lazy.
 * Earth-That-Was: Old Earth is frequently referred to as a hellhole by anyone who discusses it, as it's succumbed to horrific overpopulation despite galactic emigration, and said emigration has also drained off its best and brightest.
 * Eternal Sexual Freedom: Lazarus' mother, Maureen, had this value system instilled in her by her father... in the late nineteenth century. She manages to conceal it beneath a very carefully maintained facade of propriety.
 * Everyone Is Bi: Except Lazarus, oddly. He claims it's due to built-in prejudices from his "Bible Belt upbringing".
 * Everyone Is Related: Within the Howard Families, this is pretty much a given due to the limited gene pool they started with and the intermingling across the centuries. Lazarus takes it to a frankly absurd extreme: it's statistically estimated that over 80 percent of people with Howard ancestry are his descendants -- 99+% if you claim a recent Howard ancestor. In fact, the novel makes a Running Gag out of the Howards he meets telling him how closely related they are.
 * Exposition of Immortality: Lazarus Long spends a great deal of time (approximately a third of the novel), discussing or remembering things that have happened to him during his 2300 year long lifetime.
 * Faster-Than-Light Travel: In Space Is an Ocean style, as interplanetary travel on the Libby drive seems to occur on a scale of weeks to months.
 * Finishing Each Other's Sentences: Laz and Lor do this, to the point of actively annoying the other characters. They find it difficult to organize their thoughts when made to speak singly -- at one point, Lazarus gets tired of the gag and orders them point blank to have one speak for both of them.
 * Fish Out of Temporal Water: Discussed by Lazarus with his Tertius family when he's contemplating Time Travel to the 1920s United States. Laz and Lor in particular want to come with him, but he categorically refuses on the grounds that they have absolutely no idea how to fit in with the "craziness" of the times in question and would end up in jail or murdered in short order. He can go only because he grew up there and knows the customs.
 * The Fog of Ages: Lazarus describes the horror and unrelenting frustration that a two thousand year memory creates.

"If it can't be expressed in figures, it is not science; it is opinion."
 * Foreshadowing: After Lazarus, they point out that he doesn't actually need to go through with his enlistment in World War One -- and specifically, that while he knows the outcome of the war in general, he can't know the outcome of his own participation because it's in his personal future. He assures them that he'll be careful; he's a veteran of countless wars and knows when to duck. Oh, Lazarus -- Tempting Fate much?
 * Fountain of Youth: Medical rejuvenation therapy, which consists at its simplest level of replacing the body's entire blood supply with cloned blood, and can go as far as cloned replacements of just about everything -- even the brain, with computer support to transfer the memories.
 * Framing Device: The Scheherezade Gambit for Lazarus' memoirs in the first part. In the second part, much of the Time Travel segment is retold through Lazarus' letters that he writes and sends to his Tertius family via Delay Mail.
 * Framing Story: The first two thirds of the novel is this for Lazarus' memoirs. The last third is a more traditional sci-fi Time Travel romp.
 * Free-Love Future: The Howard Families in general seem to have adopted extremely open and liberal attitudes toward sex over the centuries; this is explained as a natural result of their focus on genetic compatibility in procreation above traditional social mores -- make healthy babies and whatever else you do is your business. It's interesting to observe the traditions and taboos that have developed even within this system, particularly the focus on registering all children with the Families' geneticists. Lazarus observes, however, that Howards are very careful to maintain a Masquerade of conformance to the norms of whatever society they're living in, to avoid drawing attention to themselves.
 * Fully-Clothed Nudity: Discussed by Lazarus with respect to the mores of the 1910s. In particular, he is amazed by how he can be turned on by Maureen's nearly Victorian flirtatiousness despite living in a future where casual nudity is the norm.
 * Gainax Ending: The final chapter is a bit of a Mind Screw, leaving it up to the audience to interpret whether and what the cryptic final passage means.
 * "Glad to Be Alive" Sex: Discussed Trope by Lazarus in response to Dora, who has just shot a man for the first time and wonders whether she's perverse in feeling horny afterwards. He reassures her that it's perfectly normal.
 * Good Bad Girl: Lazarus' mother, Maureen. Forced to adopt the illusion of propriety by the times in which she lives, she is about as horny a woman as one could imagine. Lazarus (and by extension, Heinlein) seems to hold the opinion that the cultural ideal of a "good" girl is terribly destructive and should be maintained only to satisfy the Moral Guardians of your time.
 * Got Volunteered: Lazarus' squad in World War One, by a Jerkass lieutenant, to clear some barbed wire. Turns out that.
 * Grumpy Old Man: And damned well earned it too. If only those young whippersnappers would let him die in peace!
 * Hard on Soft Science: From The Notebooks of Lazarus Long:

"All societies are based on rules to protect pregnant women and young children. All else is surplusage, excrescence, adornment, luxury, or folly, which can — and must — be dumped in emergency to preserve this prime function. As racial survival is the only universal morality, no other basic is possible. Attempts to formulate a "perfect society" on any foundation other than "Women and children first!" is not only witless, it is automatically genocidal. Nevertheless, starry-eyed idealists (all of them male) have tried endlessly — and no doubt will keep on trying."
 * Hobbes Was Right: Lazarus feels that any sufficiently large and crowded human society inevitably devolves into tyranny. This is why, when things get too "busy" on whatever planet he's on, he grabs a bunch of like-minded folks and colonizes a fresh one. This point of view contributes to the Libertarian Aesop of the novel: a man is at his best when governed as little as possible.
 * Humanity Is Infectious: For intelligent computers, apparently, leading to Pinocchio Syndrome.
 * Humans Are Special: While Lazarus relates a few tales about encountering alien life in his explorations of the galaxy (see Methuselah's Children), none of them seem able to compete even remotely with humanity's colonial drive, even if they are physically or technologically superior. He proposes Creative Sterility as one possible explanation.
 * Humans Are White: The Howard Families were founded exclusively from Caucasians, and even though there's a Token Minority ancestor or two, Lazarus Long's future appears to be largely a white man's club. Lazarus himself disclaims issues of race when the question arises, saying that humanity is so diverse by now that the question has ceased to matter.
 * I Have Many Names: Lazarus has a truly awesome number of them.
 * Immortal Procreation Clause: Averted with gusto by Lazarus, although he did go through an asexual phase after getting tired of the mechanical aspects of sex, and before rediscovering love for its own sake -- see Everyone Is Related. It's also partly a consequence of the Howard Families' tendency to idolize/fetishize the long-lived, as nearly every female he meets goes delirious over the idea of bearing his children.
 * Immortality Seeker: As related in Methuselahs Children, the Howard Foundation was started by a rich man dying prematurely of old age, and was essentially an experiment in applied eugenics -- breed long-lived people to each other to get even longer-lived people. It was so successful that it inspired the ordinary short-lived humans to develop rejuvenation technology, and the combination of the two enables effectively indefinite human lifespans. However, natural attrition and ennui mean that Lazarus is statistically the oldest human being by a factor of at least two.
 * Instant AI, Just Add Water: When asked about this, Lazarus opines that the necessary ingredient for turning a merely extraordinarily complex computer into a sapient one is the addition of love.
 * Know When to Fold'Em: According to Lazarus, at least as important as knowing how to shoot straight is being wise enough to get out of town before the shooting starts. He ascribes his survival largely to the practical application of this kind of common sense, and the one time he fails at it is the time Death nearly catches up to him.
 * Living Forever Is Awesome: Or not, at turns, depending on the mood Lazarus is in. He gets better eventually.
 * Love Makes You Dumb: Or in this case makes you enlist in the army in World War One so as not to disappoint your mother, whom you have travelled in time to visit and have fallen in love with, despite having no personal stake in the war and knowing the outcome... of the war, that is.
 * Love Imbues Life: What gives the computer true sapience.
 * Mama's Baby, Papa's Maybe: Lazarus's grandfather, having no way to have a DNA check, comes to the erroneous conclusion that Lazarus is his illegitimate child. Given the sad upbringing Lazarus invented as a back story, this leaves him feeling very guilty.
 * Marilyn Maneuver: Done by Maureen, for Lazarus' benefit, while they visit an amusement park.
 * Masquerade: The Howard Families conceal their lengthy lifespans whenever they are among short-lived humans to avoid jealousy, which is most of the time as they're vastly outnumbered on most planets. Secundus is unique because Howards form a majority of the population and can relax there.
 * Mayfly-December Romance: Dora to Lazarus. His greatest love and, consequently, the greatest loss in his life when she inevitably passes on. He remarks that it is this more than anything that keeps Howards apart from greater human society; it's also nearly impossible to maintain the Masquerade in the presence of someone you're intimate with for years.
 * Men Are the Expendable Gender: From the notebooks:


 * The Milky Way Is the Only Way: Intergalactic expeditions are mentioned, but nobody's heard back from them yet. With the technology available, it should in theory be possible to do, especially once it's discovered that the Libby drive can enable Time Travel.
 * Mix-and-Match Man: Minerva's Wetware Body is a synthetic clone combining the best genetic traits available to the engineers that create her, including some of Lazarus'.
 * Moment Killer: Woody, to Lazarus and Maureen's would-be tryst, by virtue of stowing away in their car. Their reluctance to proceed in his presence is not so much out of concern for his innocence as for his blabber mouth.
 * Mouthy Kid: The portrayal of Lazarus' 1917 self, Woody (or Woodrow Wilson Smith, if you prefer). He's about as un-innocent as it's possible for a five-year old boy to be and Lazarus reminisces on how it took many, many applications of paddle to arse to keep him even remotely in line.
 * My Future Self and Me: Yes, Lazarus, that ornery five-year old with the flappy Dr. Dentons is you.
 * My Girl Is a Slut: Maureen, you are. And you love it. And the men in your life love it.
 * My Grandson, Myself: One of the many methods that Howards use to maintain their Masquerade is by posing as their own children or grandchildren, after careful cosmetic aging followed by "death".
 * My Skull Runneth Over: See The Fog of Ages above.
 * Named After Somebody Famous: Lazarus was born Woodrow Wilson Smith, named for U.S. president Woodrow Wilson. In-Universe, a number of names keep cropping up in Howard Family genealogy, particularly Ira (Ira Howard, Ira Johnson, and Ira Weatheral -- the third being named explicitly after the second, and the first two an apparent historical coincidence). This is discussed by the characters, and in 1917, Lazarus is privileged to observe the marriage of his older sister Nancy into the Weatheral family.
 * Naming Your Colony World: Tellus Tertius, or "Earth Three", after Lazarus and crew boogie out of Tellus Secundus, or "Earth Two".
 * New Child Left Behind: Minerva, Laz, and Lor all sleep with Lazarus prior to his departure to 1916 in an attempt to get pregnant so they'll have Someone to Remember Him By after he "gets his ass shot off".
 * Newspaper Dating: Lazarus discovers by this method that he arrived in Missouri a few years too early and is now going to have to get mixed up in, or dodge, World War One.
 * Nothing Left to Do But Die: Ira makes it his job to convince Lazarus otherwise.
 * Older Than They Look: All Howards have naturally extended lifespans even before rejuvenation therapy takes over and turns it into Really Seven Hundred Years Old.
 * The Older Immortal: Lazarus.
 * Opposite Sex Clone: The thing that gets Lazarus interested in life again -- his caretakers conspire to bear twin female clones of him.
 * Outgrown Such Silly Superstitions: The Howard Families tend to be secular, and Lazarus himself is aggressively atheistic. However, there are planets whose populations take religion very seriously and Lazarus has posed successfully as a priest on more than one occasion. He remarks that not believing makes it easier to engage in the necessary swindling.
 * Parental Incest: Lazarus discovers, on meeting his mom back in 1917, that he is incredibly horny for her. She, in turn, falls for "Ted Bronson", not knowing that he's her son from the future. Interestingly, the relationship is not consummated . Lazarus' seduction by his Opposite Sex Clones might also count, depending on one's point of view.
 * Pinocchio Syndrome: The long-term goal of many AI characters is to download themselves into a Wetware Body, most often to experience love. It is accomplished for the first time ever during the Time Skip that sets up the novel's second half.
 * The Pirates Who Don't Do Anything: Laz and Lor decide to take a turn at space piracy when they grow up. It is unrevealed if they actually hijack other ships or not.
 * Polyamory: After his rejuvenation, Lazarus takes his new family and a few others and founds the Tertius colony. After a Time Skip, we see that he's living with them in a Romanesque group marriage, with himself as a sort of presiding officer over their good-natured anarchy.
 * The Power of Love: Love is, in Lazarus' opinion, the only thing that makes life worth living for thousands of years. He gets in a Title Drop with the observation that the saddest thing about ordinary short-lifers is that they barely have time enough for it.
 * Really Seven Hundred Years Old: Among Howards, age is typically counted not in years but in rejuvenations, resulting in such anomalies as a thousand-year old man in a twenty-year old body.
 * Redheaded Hero: Lazarus' entire family is redheaded.
 * Ridiculously-Human Robots: Lazarus justifies this by deducing that sapient computers learn to be human by taking on aspects of their owners' personalities.
 * Sarcastic Confession: Lazarus remarks that one of two ways to tell a lie artistically is to tell the truth in such a manner that no one believes you. Needless to say, he's an excellent liar, having learned the art at his grandfather's knee -- more properly, by being paddled over his grandfather's knee for getting caught. He counts this as among his most important survival skills.
 * Scheherezade Gambit: Used in reverse -- Lazarus' deal with Ira is that he will agree to rejuvenation for only as long as Ira continues to listen to him tell his stories, and the whole deal is conditional on Ira finding something (not ridiculously suicidal) to do that Lazarus hasn't already done.
 * Screw Politeness, I'm a Senior!: As the oldest man alive, Lazarus feels the need to defer to nobody.
 * Screw Yourself: Faced with Lazarus' reluctance to sleep with them, Laz and Lor assert that sex with one's Opposite Sex Clones cannot be incest by definition; it's closer to masturbation. Of course it turns out that he just wanted to be convinced it was their own free choice in the matter.
 * "Seen It All" Suicide: Lazarus's reasoning for refusing rejuvenation is that the universe holds nothing new for him.
 * Shrouded in Myth: Given the reverence of the Howard families for long-lived people and the reticence of the man himself, Lazarus has acquired an almost mythological status among those who know of his existence. He himself is quick to deflate their near-worship by pointing out that he's just a "grumpy old man". To which Ira retorts that he's lived over two thousand years, so he must possess some unusual traits, even if it's just the knowledge of how to live that long.
 * Single-Minded Twins: Laz/Lor. They practice Finishing Each Other's Sentences, partly out of amusement at how it weirds people out. They also claim to be able to read each other's thoughts.
 * Skinny Dipping
 * The Slow Path: How Lazarus sends letters to his Tertius family (in 4292) from 1916-1917. Envelopes in envelopes, addressed to be opened in turn by future iterations of the Howard trustees.
 * Spaceship Girl: Dora, named by Lazarus after the woman he loved more than any other.
 * Space Western
 * Suspiciously Specific Denial: As an enlistee in World War One, Lazarus is unable to conceal the fact that he's a veteran of wars beyond count in his multiple future lifetimes. Rather than try, he instead refuses to deny the notion that he might be a deserter from the French Foreign Legion, and only occasionally salutes in a "French" manner and drops an oddly accented word in his conversation. In this way he acquires a reputation as a major badass.
 * Temporal Paradox:
 * Discussed when Lazarus travels back to the 20th century, and ultimately resolved in favor of You Already Changed the Past. However, Lazarus commits a major error in reassuring his 1917 family that, since he's from the future, he'll survive his involvement in World War One, ignoring that this is the second time through from his personal point of view. It bites him in the ass hard.
 * It is revealed in To Sail Beyond the Sunset that Lazarus relates a whole laundry list of future happenings to Maureen during his visit, which allow her to take key actions to save the Howard trust fund from the Great Depression and rescue the first manned spaceflight from bankruptcy. Predestination paradox ahoy!
 * Theme Initials: "LL". Then, "LLL". Lots of L's, anyway.
 * Theme Twin Naming: Lapis Lazuli Long and Lorelei Lee Long (Laz and Lor for short).
 * These Are Things Man Was Not Meant to Know
 * Thrown Out the Airlock: Lazarus uses this method of execution on a slave overseer that insists on boarding his vessel. Not exactly an application of super survival thinking on the latter's part.
 * Time Skip: The narrative jumps some thirteen years between the conclusion of Lazarus' rejuvenation and the arrival of Justin Foote on Tertius. It then jumps another three to five years to when Lazarus leaves on his time trip.
 * Time Travel: A heretofore unexplored aspect of the Libby FTL drive, Lazarus is asked to use this to explore all sorts of past events by the Howard Families. He eventually settles on visiting his family in 1919. Unfortunately, he makes a calculation error and ends up in 1916 instead, just prior to America's entry into World War I.
 * Time Travel Romance: Initiated in this novel between Lazarus and Maureen, it is picked up and resolved by the sequel, The Number of the Beast.
 * Tracking Device: Unbeknownst to Lazarus, his Tertius family implants one in him prior to his departure to the twentieth century. This comes in very handy when.
 * Truly Single Parent: Lazarus, to Laz and Lor.
 * Twincest: Not Laz/Lor surprisingly, but Lazarus relates a story about how he bought and freed a pair of slaves who are diploid complements of each other. That is, they are twins created by taking exactly half of the chromosome pairs of each parent and fusing them with the complementary half of the other. Thus, although technically twin brother and sister from the same parents, they are genetically unrelated to each other and can safely interbreed -- and do. Due to completely unrelated circumstances, Lazarus also concludes that they are his own descendants.
 * Unusually Uninteresting Sight: The invention of time travel, about two-thirds of the way through the novel, doesn't seem to shock or astound anyone, and is not used for any great purpose (like solving historical mysteries, trying to soften past catastrophes, or visiting the future). Instead, it's used so Lazarus can sightsee in his own childhood (and boink his mother).
 * Uplifted Animal: The mules that Lazarus and Dora work with in their colony have enhanced intelligence; some are near-human level.
 * Undead Tax Exemption: Fully exploited by the Howard families to maintain their Masquerade as ordinary short-lived humans. They find it much easier to do so in pioneering societies where people care less about your paperwork and more about your contributions.
 * We Are as Mayflies: Ordinary short-lived humans compared to Howards. Not only do they live a mere pittance of years naturally, but rejuvenation techniques don't work as well for them in the long term.
 * Wetware Body: One of the technological feats that Lazarus inspires Ira and crew to accomplish is the downloading of a computer brain into a cloned human body. Minerva is the first AI to accomplish this, but she's followed in later books by several more.
 * What Happened to the Mouse?: Invoked; Lazarus relates a story about dealing with slavers, and his audience calls him out on omitting the fate of a particular character. His response: "I wondered if you would notice that. I spaced the bastard. He went thataway, peeing blood."
 * What Is This Thing You Call Love?: Lazarus spends a great deal of his rejuvenation time debating exactly what the word "love" means with his caretakers. He calls it the slipperiest concept in the universe and keeps saying that he "knows it when he sees it", much to their frustration. A sapient computer is motivated to Become a Real Boy to discover physical love, only for Lazarus to point out that she already must understand love even to be considering the idea.
 * Who Wants to Live Forever?: A question raised by the story; apparently, the Howard Families' statistics show that the most common cause of death among their members is refusing further rejuvenations.
 * Wife Husbandry: Initiated by the young colonist Dora, who falls in love with Long as his ward. He eventually consents and reinvents his identity to switch from her father to her husband. She ends up being the greatest love of his life.
 * Write Back to the Future: Lazarus uses this method, involving letters in a series of nested envelopes, to send regular reports back to Tertius on his progress in the 1910's. They use the moment when to pinpoint when he needs to be rescued.
 * Write What You Know: The Time Travel part of this book might as well be named, "Robert Heinlein's Wish Fulfillment autobiography," as it is almost literally where and how he himself grew up, minus meeting his semi-immortal time traveling self from the future and sleeping with his mother.