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 2002". Biohydrogen III evaluates the current status of Biohydrogen research worldwide and consider future research directions.