This title contains two volumes in one. Minkowski's Collected Works are issued under the editorship of David Hilbert, with the assistance of Andreas Speiser and Hermann Weyl. Minkowski was one of those great mathematicians who did important work both in pure mathematics and in mathematical physics. The papers in this volume are in four fields: the theory of Quadratic Forms, the Geometry of Numbers, Geometry, and Physics. The text is in German.