The five-volume "Lexikon der Mathematik" offers a comprehensive overview of modern mathematics, its technical terminology and its applications in a total of about 17,000 keyword entries. The subject areas covered range from classical subject areas such as geometry, number theory and the history of mathematics - via numerical mathematics, graph theory, actuarial mathematics and optimization - to modern fields of application such as wavelets, coding theory or neural networks. Special consideration is given to the biographies of important scientists from antiquity to the present. This takes into account the fact that especially in mathematics there is a wealth of procedures, methods or even theorems named after famous personalities - e.g. Abelian group, Pythagorean theorem and Euclidean algorithm. A character.