Here's the thing: Shirer was there. He was there for the buildup, when Churchill was the only guy saying Hitler was a menace, when the buildup was in full swing, when the Nazis took Austria, then Czechoslovakia, then Poland. Shirer was all over the Third Reich.

I was in study hall in high school once, bored, and I blindly reached behind me and grabbed a book. It was this behemoth and I groaned but opened it anyway, and I fell into the part where two generals come to Rommel's house in order to force him to kill himself (or face a state trial for treason). Rommel tells his son "I've just told your mother I'll be dead in a quarter of an hour." and I was hooked.