"The Rise and Fall of the Third Reich: A History of Nazi Germany" by William L. Shirer. It's a classic history book of our century which, despite its title, primarily focuses on Hitler's raise to power in the early 30s and the long, painful and ultimately futile international attempts at avoiding WW2 in the late 30s.

It's a book I wish everyone would read, particularly everyone in a public office and the media. It's a shame that comparing politicians and their actions to Hitler has became a cliche everyone now is quick to ignore. Meanwhile there's plenty of stuff happening in the world straight from the Nazi playbook of the 30s.