The use of water as a medium for promoting organic reactions has, for the most part, been non-existent, despite the fact that water has served, and continues to serve, as the solvent in which the vast majority of biochemical processes take place. Chemists have only recently come to appreciate the enormous potential that water holds for those engaged in synthetic organic and organometallic chemistry, in part because of water's unique enthalpic and entropic properties. In this volume, an international team of authors, each taking advantage of the unique properties of water for carrying out organic transformations, is brought together in order to provide a timely and concise overview of current research. The chapters focus on the practical use of water in synthetic organic chemistry, with special emphasis on Diels-Alder reactions, Claisen rearrangements, organometallic chemistry, transition-metal catalysis, oxida- tions and reductions. I am grateful to my colleagues, J. Auge, I. Beletskaya, A. Cheprakov, F. Fringuelli, J. Gajewski, P. Gamer, S. Kobayashi, A. Lubineau, D. Parker, O. Piermatti, F. Pizzo and Y. Queneau, for participating in this venture. Their knowledge and experience have been invaluable in putting this volume together.