This work is the outcome of the Kongsberg seminar, organized by the Department of Geology at the University of Oslo in May 1995, which was intended to bring together people working on diverse aspects of fluid behaviour, to allow cross-fertilization of ideas between those working on modern fluid systems and processes, and those studying old and deep fluid processes. The participants included process-oriented geologists and geochemists with specializations in petroleum geology, ore deposits, structural geology and metamorphism, together with physicists working on the application of statistical physics to geological processes. While the book's coverage is necessarily very broad, the authors are motivated by a common aim of improving understanding by crossing traditional subject boundaries. The book provides an overview of the study of fluid processes, highlighting the difficulties of integrating their chemical and physical aspects, and providing an insight into a wide range of approaches being developed today. This book should be of interest to petrologists, geochemists, hydrogeologists and economic geologists.