Just completed "final solution" by David Cesarini. Honestly I thought Martin Gilbert's "Holocaust" was the definitive one volume history but this could rival it. Two main tenets of the book, one to claim that the Nazis didn't really have a plan and made it up as they went along. Not sure I fully agree and the author had an annoying tendency to over emphasize this point. The other tenet is to debunk the idea the holocaust was kind of sex free. He details the prevalence of rape throughout the holocaust, the selling of sex as a means of survival and the exploitation of sex on all sides. Certainly it shows racial purity claims only went so far.
It's a bit of a slog, 800 pages in paperwork but worth it in the end.