I recall loving Bernie Gunther, and recommend the first three books often. (But it's been now some years since I read them. Buyer beware.) The collision of a noir vision (an endemic social corruption, a bitterly-funny protagonist bleakly trying to just get by and occasionally drawn into the moral morass) with the historical context of those early novels (pre-/WWII Nazi Germany) always seemed an outrageous high-concept stunt, leaning toward a slick exploitation, and yet damn if Kerr didn't do it some justice.
Kerr then spent a number of years rifling through the pop thriller ranks, trying to write Crichton novels with actual characters, trying on a number of other high concepts (futuristic heist! abominable snowmen! JFK assassination!), with decreasing returns.
When I heard he'd resurrected Bernie Gunther, I was skeptical. But, no, this is a pretty damn good read: the mystery a little patly-resolved but complicated and knotty throughout, the first-person patter offering up shots of moral despair and chasers of smartassery (usually top-shelf, occasionally lowenbrau).
I look forward to the next volume, coming out in a week or so.