Dieter Kotschick earned his doctorate in mathematics from the University of Oxford in 1989. After holding postdoctoral positions @Princeton and Cambridge (England), he became a professor of mathematics@the University of Basel in Switzerland before moving to the Ludwig-Maximilians-Universität München, where he holds the chair of geometry. He is grateful to Volker Braungardt and Allyn Jackson for help with the preparation of this article. Address: Mathematisches Institut, LMU München, Theresienstrasse 39, 80333 München, Germany. Internet: dieter@member.ams.org