A very interesting book about a little-known yet fascinating figure from World War II: Admiral Wilhelm Canaris, head of German military intelligence (called the "Abwehr") from 1935-1944.
Canaris was one of the most powerful men in Nazi Germany, with direct access to Hitler and a major influence on the course of events of the war. For example, it was Canaris who was the most responsible for keeping Spain out of the war. He was also an opponent of the regime and used the resources of the Abwehr to resist the Nazis and especially the SS from taking Germany to war. Canaris was disgusted with the brutality of the SS and the Nazi ideology and saw, prophetically, that they were going to take the country to destruction.
Canaris was a brilliant man who was a master of espionage. He was also very skillful against his enemies in the SS, who wanted him destroyed and the Abwehr dissolved, which they saw as a remnant of the old, conservative, monarchist Germany. When war broke out, the Abwehr was one of the main centers of resistance to Hitler. Abwehr men even made an unsuccessful attempt on the life of Hitler, putting a bomb in his airplane that unfortunately failed to explode. Towards the end of the war, the SS and Gestapo finally amassed enough evidence against Canaris to arrest him. In April 1945, just as the war was ending, Hitler had him executed, probably to prevent him from revealing to the world his vast knowledge of Nazi atrocities after the war.