The Wages of Destruction by Adam Tooze.
It's a positively magisterial comprehensive analysis of the Germen war economy in World War 2. It brings together two of my pet interests - economics and military history. More than a few common myths about how things worked are comprehensively rebutted, using data and detailed research. For anyone with an interest in that period of history, I highly recommend it.
I'm not about to start a similar book on the British war economy.