This book consists almost entirely of papers delivered at the Seminar on partial differential equations held at Max-Planck-Institut in the spring of 1984. They give an insight into important recent research activities. Some further developments are also included.

Twisted Tori of Constant Mean Curvature in R3.- Old and New Doubly Periodic Solutions of the Sinh-Gordon Equation.- Global Existence of Small Amplitude Solutions to Nonlinear Klein-Gordon Equations in Four Space-Time Dimensions.- Global Existence of Solutions of the Yang-Mills Equations in Minkowski Spacetime.- Nonlinear Stability in Fluids and Plasmas.- Lane-Emden Equations and Related Topics in Nonlinear Elliptic and Parabolic Problems.- Parabolicity and the Liouville Property on Complete Riemannian Manifolds.- Global Analysis and Teichmüller Theory.