Gun, With Occasional Music (1994)

Backcover Synopsis: Conrad Metcalf has problems. He has a monkey on his back, a rabbit in his waiting room, and a trigger-happy kangaroo on his tail. He’s been shadowing Celeste, the wife of an Oakland urologist. Maybe falling in love with her a little at the same time. When the doctor turns up dead, Metcalf finds himself caught in a crossfire between the boys from the Inquisitor’s Office and gangsters who operate out of the back room of the Fickle Muse.

I’m a sucker for mixing SF with detective fiction, and Lethem remains faithful to both genres, a hard shelled main character, who is still human on the inside and tries to grip onto this in a world where most people have forsaken their own humanity long ago. The book has a rich and detailed future that feels real enough to make the reader uncomfortable with its bleakness and weird enough to tickle those who like strangeness. Unlike most of the stuff Lethem wrote later, it has a very straightforward plot and an ending that is both understandable and still unexpected. IMHO this is Lethem’s best book.