This book presents a compelling history of the mentality of war based on a unique source foundation. Utilizing 150,000 pages of intercepted communications from German soldiers in British and American captivity, it establishes a completely new understanding of the soldiers' mentality. In specially set up camps, prisoners of war from all branches and ranks were secretly monitored. They spoke about military secrets, their views on the enemy, on leadership, and also on the extermination of the Jews. The book offers a reconstruction of soldiers' perceptions of the war in historical real-time – an extraordinarily rich internal perspective of World War II from those soldiers who devastated large parts of Europe.