"Dead men are heavier than broken hearts."
OK, so, I am American, which means I've read quite a lot of American books. Because of that, I decided it wasn't sufficient for the book to be American; it also had to be "quintessentially American." And what's more American than a tarnished knight walking the mean streets? (Yes, yes, I know that other places have plenty of hardboiled. But they totally got the whole fast-talking, sarcastic, trenchcoated tough guy from *us.*)
Along with Cain and Hammett, Chandler painted a portrait of the quintessentially American mean streets: the tough guys, the broads, the dames, the gangsters.
To my mind, no-one was more influential on the genre--and its weird offspring, urban fantasy-- than Raymond Chandler. You like Harry Bosch? Harry Dresden? Spenser? Alex Verus? Mike Hammer? Joe Pitt? Travis McGee? Felix Castor? How about "Strangers on a Train"? "Chinatown"? "Castle"? Heck, what about Ellroy? Leonard? Connelly? Ross McDonald? William Goldman?
Say "thank you" to Raymond Chandler.