Konrad Heiden 
A History of National Socialism (RLE Responding to Fascism) [PDF ebook] 

Konrad Heiden was an influential journalist and historian of the Weimar Republic and Nazi Eras. He became an early critic of National Socialism after attending a party meeting in 1920. First published in English in 1934, A History of National Socialism provides a detailed account of the growth of the movement through the 1920’s until its assumption of full control of Germany in 1934. It argues that Nazi ideology was extremely pragmatic and able to accommodate a wide diversity of opinion in return for the unconditional support of Hitler as leader.