I read the series in the '80s when I worked in a library, so the early ones are buried deep in the memory banks somewhere. I love the little Detroit tidbits he throws in throughout the books, though; stuff like the Purple Gang running booze across the river (in cars!) during Prohibition, or the goings-on in the old Detroit PD HQ at 1300.
He also has a great trilogy of Detroit through the years, including the glory days of the automotive industry and the time of the riots in the 60s. I think some of the names are Edsel and Stress.