Felix Klein

Born in Düsseldorf on April 25, 1849, Felix Klein became one of Germany’s most important mathematicians. He worked across group theory, complex analysis, and non-Euclidean geometry, and he is especially remembered for linking geometry with transformation groups in his 1872 Erlangen program.

Klein taught at several universities, including Erlangen, Leipzig, and Göttingen. At Göttingen he helped build mathematics into a major research center, and he also cared deeply about teaching, writing and speaking about mathematics in ways that connected advanced ideas with education.

His influence reached far beyond his own papers. Along with major research contributions, he played a lasting role in the history and teaching of mathematics, and his name still appears in concepts such as the Klein bottle and the Klein model of geometry. He died on June 22, 1925.