He also enjoyed reading poetry, foreign works, and works banned by the Nazis. Throughout his life, books were a lifeline for him: When he was serving on the Eastern Front, he would write to his friends to see if they could send him more books. In the last year of his life alone he read forty books. Arrest After his Abitur, the German equivalent of Baccalauréat, in 1937, Graf did his six-month Reichsarbeitsdienst and afterwards began his medical studies at the University of Bonn. In 1938, he was arrested along with other members of the Grauer Orden and charged by a court in Mannheim with illegal youth league activities–the Bünde having been banned–in relation with his unlawful field trips, camping excursions and other meetings with the Grauer Orden. The charges were later dismissed as part of a general amnesty declared to celebrate the Anschluss. The detention had lasted three weeks. His time in jail did not weaken his decision to participate in anti-Nazi activities or organizations. Studies at the University of Bonn After his release, Graf was allowed to return to the University of Bonn to continue his medical studies. While there, Graf was required to report for military duty in August 1939. The next month, September 1939, the war officially began. At this time, the University of Bonn was closed for the course of the war. Graf had chosen the University of Bonn because his aunt and uncle lived in Bonn and offered to let him live with them, as well as the fact that many of his friends (including his then girlfriend Marianne Thoeren) went to that University. After it closed, Graf transferred to Munich University. He had completed four semesters at the University of Bonn. German army In January 1940, Graf was officially drafted as a Sanitätssoldat (medic). After completing preliminary medical training, he was shipped out to France in September 1940. After serving in France for a few months, he was then transferred to a heavy artillery unit in Belgium. In March 1940, he was transferred to the Eastern Front, having medic duties in both Serbia and Poland. While in Poland in June 1941, he saw the Warsaw Ghetto. This experience caused him to write "Terrible!" in his diary entry of 6 June 1941. He might have written more, but unfortunately during this time of upheaval, he was worried what would happen if others read his