This book had its genesis in a symposium on gas hydrates presented at the 2003 Spring National Meeting of the American Institute of Chemical Engineers. The symposium consisted of twenty papers presented in four sessions over two days. Additional guest authors were invited to provide continuity and cover topics not addressed during the symposium. Gas hydrates are a unique class of chemical compounds where molecules of one compound (the guest material) are enclosed, without bonding chemically, within an open solid lattice composed of another compound (the host material). These types of configurations are known as clathrates. The guest molecules, usually gases, are of an appropriate size such that they fit within the cage formed by the host material. Common examples of gas hydrates are carbon dioxide/water and methane/water clathrates. At standard pressure and temperature, methane hydrate contains by volume 180 times as much methane as hydrate.