I recently read "Amos Walker: The Complete Story Collection" and "The Left-handed Dollar" by Loren Estleman. Amos Walker is a fictional Detroit PI introduced by Estleman in a 1980 novel ("Motor City Blue"). "The Left-handed Dollar" is the latest of 20 novels (many of which I have also read) in the series. I found it typical, solid but in my opinion somewhat below the level of the best in the genre. I liked the short story collection a bit more. It collects the 32 previously published Walker short stories and adds a new story and an introduction by Estleman (totaling some 600+ pages). I found the stories curiously addictive, it was tempting to read just one more (sort of like potato chips). I generally don't like short stories that much but a series of short stories like this is a bit different in that it is sort of like a very episodic novel. I found I rather liked the form. The early PI writers Hammett and Chandler wrote numerous short stories which I also liked when collected but the short story seems to have largely fallen out of favor since (for market reasons with the decline of the pulp magazines).
The stories have some faults and aren't for everybody. As is traditional in the genre they exhibit a rather dark view of human nature which didn't bother me but some readers might find a bit wearing particularly when repeated for 600 pages. The plots sometimes don't hold together if you think about them too much. Walker is prone to sociological asides which I sometimes found bizarre and others might find offensive. And I didn't like the way the stories were ordered. Estleman says in the introduction that they are arranged roughly chronologically but they still jump back and forth in time a lot which I found a bit jarring. I would have preferred a strict chronological order. However I liked the collection and if you also like PI stories (of the traditional "hard-boiled" variety) you might give it a try.