Diagnosis: Murder

"Diagnosis Murder is a mystery/medical/crime drama television series starring Dick Van Dyke as Dr. Mark Sloan, a medical doctor who solves crimes with the help of his son, a homicide detective played by his real-life son Barry Van Dyke." That's directly from The Other Wiki and dammed if there is a better explanation of the show (the Van Dyke Family roadshow perhaps? Given that at least two of Barry's children turn up in the series and Dick's brother turns up as Mark's brother...)

In between saving people's lives, Mark as the chief of internal medicine also finds time to help the woefully inadequate LAPD find the constant murders that have been going around lately. The whole idea is that a patient will come in comatose under the reasoning that a landslide had knocked them out and caused internal bleeding so they died, yet under closer inspection these "rock bruises" look more like the shape you would expect after been repeatedly hit by heavy books. Steve, this man wasn't killed by rocks on a landslide but by books in a library; my diagnosis, murder.

It's woefully ridiculous but the fact that the show knows it's a stupid idea and pokes a lot of fun at itself just makes it that much more appealing. Mark doesn't solve the crimes by himself; Steve, Mark's son mentioned above, gives him reason to poke around. Also, depending on the season, he has doctors Amanda Bentley, Jack Stewart and Jesse Travis. The latter opens up a BBQ restaurant with the policeman Steve. So Amanda and Jack/Jesse will then get themselves into random danger with the killer while trying to solve the murder because clearly being highly trained doctors with lives to save isn't enough to keep them occupied and they don't have the brains to ask their police friend, Steve, to look into it for them.

It's not commonly known that this was a spinoff of Jake And The Fatman.

Contains examples of the following tropes:

 * Absentee Actor: Pushed to extremes in Season 8 when either Jesse, Amanda or both were absent from nearly every episode. There are only 6 episodes of the entire season where all 4 main characters appear, and Jesse isn't even in the series finale.
 * Actor Allusion: In one episode, Dick Van Dyke as Doctor Sloan is walking through the corridors of the hospital. As he turns a corner, he passes an internal window through which we see, not a medical procedure in progress, but a broadcast booth in black and white. It's a clip of Van Dyke in The Dick Van Dyke Show. He walks on without seeming to notice.
 * George Takei and Walter Koenig played major characters in an episode that was about alien abduction.
 * This episode also featured Wil Wheaton, Majel Barrett, Grace Lee Whitney(Yeoman Rand) and Bill Mumy(Lennier on Babylon 5).
 * Amanda Bentley was once invited to visit the set of The Young and The Restless. Several cast members of the soap appeared as themselves, and commented that Dr. Bentley bore an uncanny resemblance to Victoria Rowell(who played both Dr. Bentley and Drusilla on Y&R).
 * Steve, discussing 'classic' TV themes, mentioned Airwolf. Barry Van Dyke played st John in Airwolf's third season.
 * Adam Westing: Adam West himself cameos as a washed-up actor who was made famous by playing half of a crime-fighting duo, Tuttle and the Mummy.
 * Amateur Sleuth: Dr. Mark Sloan.
 * Banana In the Tailpipe: Used with a wad of cash in the tailpipe.
 * Bunny Ears Lawyer: Dr. Sloan has raised eccentricity to a high art(he's been known to make his rounds on roller-skates), but his skills as a doctor and as a consultant to the police more than make up for that.
 * Chuck Cunningham Syndrome: Delores Mitchell and Norman Briggs.
 * Church of Happyology: Earthonomy, a cult with ridiculous mafia-like connections. They kill a reporter who was investigating them and attempt to kill another reporter. One suspect is even a closeted gay actor obviously based on... a certain actor.
 * Connect the Deaths: A serial bomber wrote the name of her dead father on the city map. The absurdity of this is Lampshaded by Steve, who draws a pig in the same pattern, though of course Dr. Sloan is right.
 * Contractual Purity: An episode of Diagnosis Murder had the murder victim (the Executive Head of a PAX-style Christian TV network) given a fatal heart attack by video clips sliced into a show she's reviewing that had images of a lookalike practicing Satanism (which she did in college), something that would ruin anyone's career, let alone hers.
 * Criminal Doppelganger: The two-parter episode "Gangland" centered on a recently paroled mob boss who bore a striking resemblance to Dr. Mark Sloan (both roles played by Dick Van Dyke)
 * Dangerously Genre Savvy: Dr. Mark Sloan demonstrated a shocking amount of Genre Savvy in a multi-part arc in which he was kidnapped by the deranged son and daughter of a serial bomber who had been executed as a result of Sloan's investigation. Even as a hostage he succeeded in playing the siblings against each other while providing clues to his son the cop and other partners in crime-solving that led them to the kidnappers. A federal agent assigned to the case supplied the lampshade; "Some people you should not kidnap! I swear, if Mark Sloan is your enemy, shoot him in the head, otherwise he will make you suffer!"
 * Diabolus Ex Nihilo: The motive of the culprit in "Rear Windows '98" is never revealed.
 * Directed by Cast Member: One episode is directed by Barry Van Dyke.
 * Disposing of a Body: One episode (that was kind of a ghost story) had one corpse turned into an exhibit skeleton.
 * Everything Is Online
 * Evil Twin
 * Friend on the Force: Mark's son.
 * Gangsta Style: Played with in an episode where Mark Sloan is at a gun range being shown how to use a pistol. He fires off a few rounds normally (with realistic loudness and recoil) and then asks the man who was showing him whether he could fire it sideways "like on TV", twisting it to the side to show him what he meant. While the instructor starts saying why it's a bad idea, Mark fires the gun anyway by accident and the recoil flings it out of his hand with great ease and force - which creates a big enough diversion for another character to sneak past.
 * Gold Digger: The victim in "Open and Shut"
 * Hollywood Hacking: "Rear Windows '98"
 * Homage: DM has done episodes that honor TV doctors of the past ("Physician, Murder Thyself" with Chad Everett, Wayne Rogers, Jack Klugman and Bernie Kopell), TV spies of the past ("Discards" with Robert Culp, Barbara Bain, Robert Vaughn and Patrick MacNee), TV cops of the past ("Murder Blues" with Fred Dryer, Angie Dickinson, Martin Milner, Kent McCord and James Darren), Emergency! ("Malibu Fire" with Emergency regulars Randolph Mantooth and Robert Fuller), MASH;; ("Drill For Death", with a number of cast members from both the movie and TV versions), Star Trek the Original Series ("Alienated", with Trek regulars Walter Koenig, George Takei, Grace Lee Whitney and Majel Barrett, plus TNG's Wil Wheaton and Lost in Space's Bill Mumy) and Happy Days / Laverne and Shirley("Food Fight" featuring Pat Morita, Don Most, Erin Moran and David L. "Squiggy" Lander).
 * Inconvenient Hippocratic Oath: In one episode, Dr. Sloan is at a retirement home disguised as a wheelchair-bound senile person in order to investigate corruption. At one point, another character needs emergency medical treatment, so Sloan has to irrevocably blow his cover in front of all the staff and residents to help.
 * Interdisciplinary Sleuth: Dr. Sloan uses his medical knowledge to solve crimes.
 * Jack the Ripoff: The title character of the tie-in novel The Silent Partner is a serial copycat: one copycat each for multiple serial killers.
 * Karma Houdini: In "Rear Windows '98," Susan doesn't even apologise for falsely accusing Jesse of intentionally poisoning her.
 * The Killer Was Left-Handed: Almost used in an episode where the killer must be right handed. This lets the left handed man off, until it's revealed that everyone is innocent. Since someone must be guilty, it turns out the lefty is ambidextrous.
 * Let's Get Dangerous: The normally calm and by the book Mark and Steve will resort to Jack Bauer Interrogation Techniques if their friends or family are threatened.
 * The Movie
 * Mystery of the Week
 * Not-So-Fake Prop Weapon: One episode featured a morning show staging a shooting between the hosts as a publicity stunt. Someone switched the real bullets for blanks and the cohost gets shot.
 * Obfuscating Disability
 * Older Than They Look: Jesse Travis got this on occasion. How gracefully he reacted depended on how snotty the other person acted.
 * Phone Trace Race: In one episode, the killer who had previously dodged phone traces allows the call to be traced to a pay phone to distract the police.
 * Poorly-Disguised Pilot: The episode "Blood Ties" was clearly a pilot for a series featuring the two female police officers who were showcased.
 * Pregnant Hostage: In "Baby Boom."
 * Real Life Relative: Barry Van Dyke is Dick Van Dyke's son. Other members of the Van Dyke family appeared at various times during the show's run, including Dick's brother Jerry and daughter Stacy in one episode each as Dr. Mark's brother and daughter respectively. Barry's four children all appeared in multiple episodes, although not as Sloan family members: Carey as six different characters in as many episodes; Shane as four, the last of whom became a regular supporting role in the show's concluding months; Wes as three; and Taryn in three episodes. All four appeared together in two separate episodes, which therefore share the highest rating of 6.0 on the Van Dyke Scale...
 * Real Life Writes the Plot: Victoria Rowell's real-life pregnancy in Season Three resulted in Amanda Bentley falling in love and marrying a US soldier who was stationed in Bosnia. Her husband remained The Unseen, and from season four on, depending on the epidode, either they got divorced or he died in a plane crash.
 * Reality Subtext: The home movie footage of Dr. Sloan and his son is Dick Van Dyke's actual home movie.
 * Reverse Whodunnit
 * Right-Wing Militia Fanatic: One episode featured a militia group trying to separate the US West Coast into a state for whites, complete with the We Are Everywhere threat and a stolen nuke.
 * Suicide by Cop: Subverted: the bad guy has a degenerative disease not covered by insurance (pre-existing condition), and spends the entire episode goading Steve into killing him. It is implied that part of Steve's refusal to do so is because the villain went a bit too far. Good Is Not Always Nice, perhaps?
 * Suspiciously Similar Substitute: Dr. Jesse Travis replacing Dr. Jack Stewart for the 1995-96 season.
 * Tinkle in the Eye: The characters discuss how this always happens on TV before it actually happens.
 * Tontine
 * Twin Switch: A man murders his twin, then takes over his twin's life.
 * Uncanny Family Resemblance
 * Unsettling Gender Reveal: In one episode, the victim was an MTF post-op TS, and Steve had been flirting with her before she was killed. To the show's credit, the victim was portrayed as a sympathetic character and none of the main characters freaked out about it. In fact,, and the murderer is portrayed as a Jerkass.
 * We Can Rule Together: Oddly invoked and lampshaded in the episode "Blood Ties" (a backdoor pilot for a cop drama involving two female police officers). A team of renegade cops, who have taken to murdering known felons and placing "organ donor" stickers on their drivers licenses so their organs can be harvested for transplants, tries to convince the two protagonist cops to join them. One of the two officers comments that this reminded her of a James Bond scene, where the villain tries to convince Bond to join him in taking over the world. She says, "All Bond had to do was say 'yes', and he could buy enough time for his fellow agents to rescue him and save the day. I never understood why he never said 'yes'...until now. The answer is 'no'."
 * Welcome to The Real World
 * We Would Have Told You But: