Playback, Paperback

In noir master Raymond Chandler's Playback, Philip Marlowe is hired by an influential lawyer he's never heard of to tail a gorgeous redhead, but then decides he'd rather help out the redhead. She's been acquitted of her alcoholic husband's murder, but her father-in-law prefers not to take the court's word for it.
"Chandler wrote like a slumming angel and invested the sun-blinded streets of Los Angeles with a romantic presence: " -- Ross Macdonald