The Rise and Fall of the Third Reich is a book that all policy makers should read. It details the rise and fall of Adolf's leadership of Germany, including both the external (e.g. deficits, debt, The Depression) and internal (organization, oration, trickery) conditions that allowed him to thrive.
Hitler's rise to absolute power is all the more remarkable considering Germany was a democracy at the time. Through his popularity, his suppression of opposition, and a great deal of deception, however, he was able to knock down various institutions that were meant to separate powers. By the end of his rule, he officially *was* the law; whatever he said went, even if it contradicted what was written as law.
Unlike a lot of pieces written about this period, the author manages to stay away from offering opinions on how historical events played out, instead sticking to the facts as they are recorded in captured German documents, recorded speeches, corroborated testimony and other written communications (German generals appear to have kept extensive diaries in many cases).
Nor is the book written by an outsider whose only contact with the war is through documents. Shirer was an American reporter stationed in Germany during the war. He traveled with Germany troops at times, and was often censored. When he got word in 1940 that the Nazis were building an espionage case against him (which carries the death penalty), he left.
From the secret German documents, it is pretty clear that Hitler was bent on acquiring new territories. But in public speeches, he consistently made overtures for peace, promising his intentions were benign. At the time, this fooled British Prime Minster Chamberlain, who allowed Germany to capture territory while building up its defenses. Lesson: watch what a person does, not what he says.
The book is also a reminder of how times change quickly. The author's prejudices against homosexuality are made rather clear at certain points; this is not something a credible author/reporter could do today!
If you plan to read it, set aside a good amount of time; the book is more than 1200 pages long! But well worth it, in my opinion.