For most mathematicians and many mathematical physicists the name Erich K?hler is strongly tied to important geometric notions such as K?hler metrics, K?hler manifolds and K?hler groups. They all go back to a paper of 14 pages written in 1932. This, however, is just a small part of K?hler's many outstanding achievements which cover an unusually wide area: From celestial mechanics he got into complex function theory, differential equations, analytic...