This book is the culmination of the NATO Advanced Study Institute on The Mathematics of Models for Climatology and Environment which was held at Puerto de la Cruz ,Tenerife, Spain during 11-21 January 1995. One of the main goals of the ASI was to establish a bridge between mathematical modellers on the one hand and physical oceanographers and climatologists on the other. The book is divided into fourth parts containing a total of 16 chapters: Parts I, II and III are devoted to general models and Part IV to models related to some local problems. Most of the mathematical models here considered involve systems of nonlinear partial differential equations. The mathemat­ ical treatment cover a large list of subjects: existence and uniqueness for well-possed problems, large time behaviour, stability, bifurcation,diagrams of equilibria, conditions for the occurrence of interfaces or free boundaries, numerical algorithms and its implementation, controllability of the problems, etc. I thank Jacques- Louis Lions and Cornelius Johannes van Duijn for their guidance and collaboration as co-directors of the AS!. I also thank J.F.Padial and G. Diaz for their help in the planning and conduct of the ASI as well as in the preparation of this book.