The man who did the impossible There are a few extraordinary people and Arne Beurling is definitely one of them. It was in fact because of this man that Sweden avoided being occupied during World War II. By using only pen and paper, he made all the difference between war and peace. Arne Beurling was born on 3 February 1905. He showed a natural ability for mathematics already at an early age, and in 1937 he became Professor of Mathematics at Uppsala University. There he worked with the theory of generalising functions, differential equations, harmonic analysis, Dirichlet series and potential theory. Foreign mathematicians (especially American mathematicians) were fascinated by the Swede. They made pilgrimages to Uppsala in order to meet Beurling and to study his genius. When World War II broke out, Beurling started to work for the Swedish Defence Staff. His job was to break the codes that were used by the different countries at war that surrounded Sweden. When the Germans invaded Norway in 1940, the Swedes were given the opportunity to intercept messages sent by the German telex and tele-traffic as this means of communication went via Sweden.