This book presents a collection of selected contributions on recent results in nonlinear partial differential equations from participants to an international conference held in Fes, Morocco in 1994. The emphasis is on nonlinear elliptic boundary value problems, but there are also papers deveoted to related areas such as monotone operator theory, calculus of variations, Hamiltonian systems and periodic solutions. Some of the papers are exhaustive surveys, while others contain new results,published here for the first time. This book will be of particular interest to graduate or postgraduate students as well as to specialists in these areas.