The Man in the Crooked Hat by Harry Dolan is terrific. He writes really well and has such original plots and interesting characters. In this book, Jack Pellum is just starting out as an independent private investigator after a terrible year in which his wife was murdered and he left the Detroit police force. He is rightly obsessed with finding his wife's killer, who may or may not be connected to the titular man. The secondary characters are also believable and well developed. The twisted path to different truths is intriguing. Highly recommended.