The chapters in this book are based upon lectures given at the NATO Advanced Study Institute on Synthetic Membranes (June 26-July 8, 1983, Alcabideche, Portugal), which provided an integrated presentation of syn thetic membrane science and technology in three broad areas. Currently available membrane formation mechanisms are reviewed, as well as the manner in which synthesis conditions can be controlled to achieve desired membrane structures. Membrane performance in a specific separa tionprocess involves complex phenomena, the understanding of which re quires a multidisciplinary approach encompassing polymer chemistry, phys ical chemistry, and chemical engineering. Progress toward a global understanding of membrane phenomena is described in chapters on the principles of membrane transport. The chapters on membrane processes and applications highlight both established and emerging membrane processes, and elucidate their myriad applications. It is our hope that this book will be an enduring, comprehensive compen dium of the state of knowledge in the field of synthetic membranes. We have been encouraged in that hope by numerous expressions of interest in the book, coming from a variety of potential users.