I just finished that myself and I HIGHLY recommend it. Wachsmann is University of London, and this is probably his life's work. Warning: it is not a comfortable read, and that's a gross understatement.
From the other side, Black Edelweiss, A Memoir of Combat and Conscience, by Johann Voss. Voss (not his real name) is now an international lawyer - this was his story of combat in the far North (Norway) versus the Soviets, and a harrowing march south. For some reason the people seemed to hate his unit more than the other German units but he didn't know why - the Black Edelweiss is the unit badge of the Waffen SS but he was unaware of what the SS had been doing in the rest of Europe. As a POW he was assigned to an American attorney prosecuting the Nuremberg trials as a translator, and he found out what the SS had been doing from testimony and unimpeachable evidence. That realization was as bad as combat. He went into international law as a consequence. Fascinating story.
The Military Revolution: Military Innovation and the Rise of the West, 1500-1800 by Geoffrey Parker. A marvelous case presented by a superb historian. Why were the military innovations of the West so dominating during this period? Why did those of the East, formerly so overwhelming, fade? Great stuff.
Spandau: The Secret Diaries by Albert Speer. Finally found a decent copy of this. It's what Speer wrote during his 20 years of imprisonment following WWII. Highly perceptive studies of his fellow prisoners including Admirals Raeder and Doenitz, Baldur von Shirach, and most interesting of all, Rudolf Hess, and, of course, Hitler himself. Speer insisted to the end that he did not know about the extermination camps; recent evidence indicates that he probably did. His own words weren't exactly self-exculpatory: "If I did not know it was because I did not want to know."
A correction: Voss’s memoirs are of his combat in Finland, not Norway. Mea culpa.
I have that on my wish list. I've heard that it's quite good.