Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Johannes Juilfs, also known by the alias Mathias Jules, (1911 1995) was a German theoretical and experimental physicist. He was a member of the Sturmabteilung (SA) and then, in 1933, of the Schutzstaffel (SS). Prior to World War II, he was one of three SS staff physicists who investigated the physicist Werner Heisenberg during the Heisenberg Affair, instigated, in part, by the ideological deutsche Physik (German physics) movement. During the war, he worked as a theoretical physics assistant at the Kaiser Wilhelm Institute for Physics.