Hydrogen is an almost ideal fuel and its wider use will result in an improvement in the environment due to factors including decreased air pollution. Hydrogen is the element of greatest abundance in the universe; however, its production from renewable resources remains a major challenge. The papers presented within this volume enhance and expand upon presentations made at the ''Workshop on Biohydrogen 99'', Tsukuba, Japan. The contents evaluate the current status of Biohydrogen research worldwide and consider future research directions. Contributions from leading international experts cover the breadth of Biohydrogen R and D, from production to genetic engineering and molecular biology. This volume is designed to be an invaluable resource for researchers and other professionals who wish to obtain an overview of Biohydrogen R and D.