Helmut Wielandt (19 December 1910 – 14 February 2001) was a German mathematician who worked on permutation groups. He was born in Niedereggenen, Lörrach, Germany. He gave a plenary lecture Entwicklungslinien in der Strukturtheorie der endlichen Gruppen (Lines of Development in the Structure Theory of Finite Groups) at the International Congress of Mathematicians (ICM) in 1958 at Edinburgh and was an Invited Speaker with talk Bedingungen für die Konjugiertheit von Untergruppen endlicher Gruppen (Conditions for the Conjugacy of Finite Groups) at the ICM in 1962 in Stockholm. Among his work in Algebra is an elegant proof of the Sylow Theorems (replacing an older cumbersome proof involving double cosets) that is in the standard textbooks on Abstract Algebra, i.e. Group Theory. Source: Wikipedia (en)