Hollywood Station (Hollywood Station Series #1) by Joseph Wambaugh

If you got a call that Batman was assaulting Spider-Man, and the person who called it in was Marilyn Monroe, and Marilyn was actually a six foot three transvestite, there's only one place you could be: nothing is too weird for the city of Los Angeles. For the cops of Hollywood Station policing crackheads dressed as cartoon characters is business as usual, but add a diamond robbery, the Russian mafia and a pair of cluelessly ambitious crystal meth addicts and something has got to give . . . 

Told with grit and humour, Hollywood Station is the story of cops working the streets at the same time as the streets work the cops and marks the triumphant return, after a twenty year absence, of crime fiction's greatest master.