The Book of Night with Moon

The Book of Night with Moon/Feline Wizards series is a sister series to Young Wizards, also written by Diane Duane, following the adventures of a group of wizardly cats who maintain the worldgates in New York City. Currently there are two books: The Book of Night with Moon, published in 1997, and To Visit the Queen, published in 1999. The series is targeted to adults instead of a Young Adult audience, but the only difference this makes is the presence of some explicit references to sexuality and the fact that the viewpoint character, Rhiow, is an adult cat.

These books provide examples of:

 * Alternate Timeline: One pops up in the second book and the plot revolves around stopping it from overwriting the protagonists' timeline.
 * Exclusively Evil –
 * Being Good Sucks
 * Boisterous Bruiser - Urruah
 * Bratty Half-Pint: Arhu starts out pretty bratty.
 * Call a Rabbit a Smeerp: There's a fair amount of it, between the use of cats' words for familiar things (like houff for "dog") and the mangled versions of human names for other things (cats aren't really equipped to pronounce most consonants).
 * Cats Are Magic
 * Cats Have Nine Lives: They reincarnate eight times, keeping their personalities and some but not all of their memories. A cat can feel what life they're on, and the subject of how many lives one has left is fairly personal, something it's okay to divulge but not okay to just brazenly ask about.
 * Out of Continues: Turns out Saash is on her ninth life.
 * Chess Motifs - the cats have their own strategy game depending on position, ownership of people and things, etc.
 * Dark Is Not Evil
 * Deadpan Snarker - Rhiow
 * Deface of the Moon: They don't bother writing a message or anything, but the Victorians with nukes test their nukes on the Moon, sending a very visible message to everyone else on the planet.
 * Delayed Ripple Effect: In the second book.
 * Dinosaurs Are Dragons
 * Doing in the Wizard – Magic operates via String Theory and the cat wizards manipulate the "strings."
 * Fictionary: The important words in Ailurin (some of which have simple translations, but most of them don't) are untranslated, with a glossary provided at the back of the book.
 * God of Evil - the Lone Power
 * Headbutting Heroes - Urruah and Arhu
 * Historical Person Punchline: is Arthur Conan Doyle.
 * Humans by Any Other Name: The cats call humans ehhif.
 * Humans Through Alien Eyes
 * Insufferable Genius: Fhrio.
 * Intellectual Animal: The cats are basically a society of these; they're as cognitively capable as humans, but they don't think like humans. They're also physically incapable of building much of anything and normally speak their language at a volume inaudible to humans, which mostly explains why humans aren't aware that cats are that smart.
 * Many other species are said to be this, and can produce wizards; canine and falcon wizards are discussed, but not shown.
 * Interspecies Friendship - the cat wizards and the human wizards. Also
 * Literary Allusion Title: The second book, To Visit the Queen.
 * Long Lost Sibling -
 * My Kung Fu Is Stronger Than Yours - Urruah has the most Life Energy at his disposal and acts as a power source for the rest of the team.
 * Mythopoeia
 * No Biological Sex: Though they have gender identities, spayed or neutered cats are treated as basically this by cat society.
 * Of the People: The cats' name for their species is People. They don't actually call other species "not-people", though. They look down on humans somewhat (in a patronising way, rather than a xenophobic way), but not as much as they look down on dogs, birds, rats, and other animals that are either prey or competition for cats.
 * Oracular Urchin: Arhu develops into one, although his personality remains fairly down-to-earth.
 * Proud Warrior Species Guy - Ith
 * Reptiles Are Abhorrent - played with.
 * Starfish Language: Ailurin qualifies from a human perspective, though there are at least two humans who learned to speak it anyway. It's a tonal language with 37 vowels, extremely sensitive to mispronunciation. The transcriptions are both rather approximate and condensed to be more accessible to the human audience. Also, what cats consider normal volume is inaudible to humans; to be heard by a human they have to shout.
 * The bit about volume is a little Truth in Television; cats really do have extraordinary hearing, and they can easily pick up a quiet sound from halfway down the block.
 * Steampunk: The alternate timeline from the second book is a pretty textbook case. But they have nukes, which they first use to Deface of the Moon and then to blow themselves up in the 1880s.
 * Stuffed Into the Fridge: The Lone Power arranges for Rhiow's owner Hhuha/Susan to get hit by a taxi in the first book, to distract her with grief and discourage her from interfering.
 * Timeline-Altering MacGuffin: From the second book, Van Nostrand's Scientific Encyclopedia, a massive book dropped by an unfortunate London student who was briefly diverted into the year 1874. It contains pretty much all the information about modern science and technology you could possibly need.
 * Time Travel: The second book revolves around it.
 * Trademark Favorite Food - cheese... it's solid milk!
 * Yandere: eventually turns out to be one.