The four enemy missions of U-509 are described in the third volume of the documentation about Willy Meyer, among other things, based on the official war diaries of the submarine, which were at the time classified as "Secret Command Matter." The photos, mostly from private archives, were taken by Willy Meyer and his comrades aboard the submarine. The private documents come from the estate of the author's grandparents. These historically valuable materials are being published for the first time.