Answer
Erich Kästner served in the German Army during World War I. He was drafted into the military in 1917 and served on the Western Front. Kästner's experiences in the war had a profound impact on his life and work. He later wrote about his experiences in his novel "Fabian: The Story of a Moralist" (1931), which is considered one of the most important German novels of the 20th century.