During the last six years one of the most productive of the International Energy Agency (IEA) networks on renewable energy, has been the network entitled “Biotechnology for the conversion of Lignocellulosics”. One of the reasons for the success of the network has been the interaction of molecular biologists, microbiologists, chemists, engineers, etc., all working together on the technical and economic aspects of biomass conversion of ethanol. The authors of the various chapters in this book are part of this network and were selected for their familiarity with either a specific step of a bioconversion process or for their ability to assess the technical and economic aspects of the overall process. The chapters describe the technical advances that have been made in the various process steps, and also indicate the probable configuration of a biomass to ethanol plant. This book will interest researchers, engineers and industrialists.