Siegfried Flügge was born on March 16, 1912 in Dresden. He studied physics in Dresden, Frankfurt, and Göttingen, where he completed his doctorate in 1933 under the supervision of Max Born. After holding positions at the universities of Frankfurt and Leipzig, he worked in Berlin as a theorist-in-residence with Otto Hahn and Lise Meitner. Here he witnessed the historical moment of nuclear fission and took an active part in its interpretation.In 1944 Flügge became professor in Königsberg. He taught in Göttingen from 1945 to 1947 when he accepted a chair in theoretical physics in Marburg. Finally, in 1961, he followed a call to Freiburg where he taught until his retirement in 1977. He died in December 1997.Flügge worked primarily in theoretical nuclear physics, but he also published widely in quantum physics, astrophysics, and other areas. His numerous textbooks served as standard references to generations of students. He also single-handedly edited the monumental Encyclopedia of Physics.