Sep Ruf was a German architect and designer strongly associated with the Bauhaus group. He was one of the representatives of modern architecture in Germany after World War II. His elegant buildings received high credits in Germany and Europe and his German pavilion of the Expo 58 in Brussels, built together with Egon Eiermann, achieved worldwide recognition. He attended the Interbau 1957 in Berlin-Hansaviertel and was one of the three architects who had the top secret order to create the governmental buildings in the new capital city of the Federal Republic of Germany, Bonn. His best known building was the residence for the Federal Chancellor of the Federal Republic of Germany, built for Ludwig Erhard, the so-called Chancellor's Bungalow.

Expo 58, also known as the 1958 Brussels World's Fair, was a world's fair held on the Heysel/Heizel Plateau in Brussels, Belgium, from 17 April to 19 October 1958. It was the first major world's fair registered under the Bureau International des Expositions (BIE) after World War II.