This collection of essays is dedicated to Professor Klaus Neumann, Head and Chair of the Institute for Economic Theory and Operations Research WiOR at the University of Karlsruhe. On the occasion of his emeritation, disciples, colleagues, scientific companions, and friends coming from dif­ ferent fields have contributed their perspectives on Operations Research to form a broad view on the discipline. The papers are organized in four parts on optimization, OR in production and service management, OR in logistics, and interdisciplinary approaches. We thank all the authors for their participation in publishing this volume. Mrs. Ute Wrasmann from Deutscher Universitats-Verlag deserves credit for her interest and assis­ tance on this project. Finally, we would like to express our gratitude to PTV Planung Transport Verkehr AG in Karlsruhe and to numerous former WiOR colleagues for their financial support. Klaus Neumann was born in Liegnitz (Silesia) in 1937. Prom 1955 to 1961 he studied mathematics at the Technical Universities of Dresden and Munich. His first paper on analog computers and dynamic programming was published less than two years later. In 1964 he obtained a Ph. D. in mathematics under the supervision of Josef Heinhold in Munich. After a two-year stay in industry, he returned to his alma mater, working on the fields of dynamic optimization and control theory.