Recently there has been a widespread resurgence of interest in the applications of hydrogen as a "clean fuel" with its potential for local electricity production and use in transport. The last five years have seen breakthroughs in our understanding of the nature, structure and biosynthesis of hydrogenases. This book is a timely description of these developments, taking a lucid, multidisciplinary approach. Scientists in fields such as clean technology, biochemistry, electrochemistry, agriculture and general biotechnology will find this an accessible resource bringing together the many facets of these enzymes.