For some reason I had got the premise of this stuck in my head as "the Nazis attempted a secret Everest expedition in the 30s" and was therefore expecting an odd side chapter in mountaineering history. Turns out it's got nothing to do with that; the expedition went to Tibet to shoot and stuff a shitload of animals (for "science"), persuade as many locals as they could to let them measure their heads and bodies (for "science"), and look for traces of ancient Aryans (for "science"). There were a lot of interesting bits as the author delves into the occult side of national socialism, especially Himmler's obsession with ancient, otherworldly origins of Aryans and his determination to establish a (bug-shaggingly crazy) scientific basis for same. The result is a whole lot of bizarre pseudoscience and cryptohistory, mixed up with a generous helping of gross/bogus race theory. The book focused heavily on expedition leader Schäfer's full complicity with Himmler and the SS who were funding large parts of the expedition, and how he managed to talk his way out of any accountability after the war. Pretty much same for other members of the expedition, including the dude who was heavily involved in the murder of 86 concentration camp inmates for his sick pseudoscientific experiments. Depressing.
The style was a bit overly sneery (mate, no sane person is going to disagree with you about these men being nazis first, "explorers" a proudly self-declared second, and scientists a distant third), but it was definitely educational.