single- cell protein production, as biocatalysts for the production of fine chemicals, draws strong attention. The aim of this series is to provide annual reviews on the biochemistry, physiology, ecology, genetics, and application of microbial autotrophs and methylotrophs. The scope of the series includes all aspects of the biology of these microbes, and will deal with phototrophic and chemolithotrophic prokaryotic autotrophs, carboxydobacteria, acetogenic-, methanogenic- and methylotrophic bacteria, as well as methylotrophic eukaryotes. The exciting advances made in recent years in the study of these organisms is reflected in the chapters of this first volume which have been written by experts in the field. We would like to express our sincere thanks to all the contributors for their stimulating and comprehensive chapters.