I have recently found another author I can not believe I wasn't exposed to and consequently didn't read when he was active.
Ross Thomas.
This writer is Oh, So much fun.
Talk about writing the best page turner. Just brilliant stuff!
Here's an appreciation written after his death in 2005
So far I've read
The Fools in Town Are On Our Side and
Briarpatch and
Cast a Yellow Shadow and I'll put these works up there with Graham Greene, Raymond Chandler or John LeCarre.
Here's the Wiki, I hope you pick up any of these titles, read and enjoy!