The Seventh International Colloquium on Differential Equations was organized by the Institute of Basic Science of Inha University, the International Federation of Nonlinear Analysts, the Mathematical Society of Japan, the Pharmaceutical Faculty of the Medical University of Sofia, the University of Catania, and UNESCO, with the cooperation of a number of international mathematical organizations, and was held at the Technical University of Plovdiv, Bulgaria, from 18 to 23 August 1996. This proceedings volume contains selected talks which deal with various aspects of differential and partial differential equations.