Hitler's Enforcers: The Gestapo and the SS Security Service in the Nazi Revolution | George C. Browder
Based on research at 34 archives in Germany and the United States, this socio-organizational history of the Gestapo, the SD, and the regular detectives of the Third Reich, from 1932-1937, is the first such study to benefit from the German documents captured by the Soviets and Poles and kept secret until recent years.