King Rat is an urban fantasy novel by British writer China Miéville, published in 1998.

As King Rat takes Saul under his wing, the young man is quickly embroiled in a centuries-old rivalry.

Saul Garamond returns to the flat he shares with his father in London late one evening, skipping on greetings and heading straight to bed.

After spending most of a day being interrogated and in a holding cell, Saul finds he has a mysterious visitor, who introduces himself as King Rat.

Being half rat, his two primary abilities are being able to eat anything, even garbage, and squeezing into holes and shadows too small for other creatures.

Meanwhile, Saul's friend Natasha Karadjian, a drum and bass musician, begins to write and record new music with a flautist named Pete.

Two of their other mutual friends, Fabian and Kay, are unnerved by this stranger but find it hard not to like the music the two are making.

Even with his newfound powers, Saul is forced to stay in the shadows with King Rat, but cannot forget his own friends and past.

Fabian is interrogated by the police again and he realises that the flute left behind when Saul was attacked belongs to Pete.

He begins to notice something is wrong in the sewer as well, as the rats have disappeared, their scratching replaced by a new sound, music.

Saul and King Rat are unsung heroes of the club but they both know they can never be a part of the world they just saved.

Reviewing the book for The Magazine of Fantasy & Science Fiction, Charles de Lint praised King Rat as "a riveting, brilliant novel... the inspired mingling of old mythic matter with the contemporary world, ... an utter delight.