I’ve just finished Metropolis, and what a farewell book.
Sadly Philip Kerr died last year, so this is the last Bernie Gunther book. This superb series of fourteen books traces the rise and fall of Nazi Germany through the eyes of Bernie Gunther, an anti-Nazi policeman, who is forced to work, at the same time, for and against his Nazi bosses. 
Metropolis, Philip Kerr, $32.99