SS General Hans Kammler was one of the worst of the Nazi war criminals. He was the architect of the Nazis' death camp technology. He designed the gas chambers and crematoria that Nazis used to kill and dispose of millions of Jewish prisoners during World War II. He personally ordered the execution of citizens. After the war, Kammler mysteriously disappeared. But this startling new book alleges Kammler was actually hidden by the American government in exchange for his technology and weapons secrets.