March Violets, set in 1936 Nazi Germany, introduces Bernie Gunter, a former police detective who, disgruntled with the Nazi bureaucracy, resigned from his position and is now employed as a private detective. Kerr does a good job of capturing the viciousness, corruption and seediness of Nazi Germany. Gunther is an interesting character, but I felt at times that Kerr overdoes the hardened, wise-cracking detective routine. The plot moves briskly, but occasionally it lurches from from one plot twist to another, and the ending is slightly unconvincing. But Kerr has apparently had success with Bernie Gunther, and there are ten novels in the series, with an eleventh due in 2016. I might try the 2nd installment, The Pale Criminal.
Update: Philip Kerr died in 2018, and had written 12 books in the Bernie Gunther series.
Notice: If you click on an Amazon link above, and purchase the book, I am supposed to make a tiny commission on the sale. Just so you know.