In 2001, the German military historian Sönke Neitzel spotted a footnote in a book about the U-boat war that referred to recently declassified transcripts of conversations between captured German submariners secretly recorded at a POW camp at Trent Park on the outskirts of London. Neitzel was intrigued and visited the UK National Archives to see what else they contained. He found an extraordinary hoard of documents generated by the covert surveillance of 10,000 captive officers and other ranks from the German navy, the Luftwaffe, the army and the Waffen-SS. In all there were 48,000 pages of transcripts. Neitzel contacted the social psychologist Harald Welzer, who had previously studied Nazi perpetrators, and together they approached German foundations to assemble a research team. The result of their labour is an unprecedented insight into the minds of German military personnel. Whether Neitzel and Welzer’s analysis is quite as original or illuminating is another matter.