Biotechnology is now one of the major growth areas in science and engineering and within this broad discipline enzyme technology is one of the areas earmarked for special and significant developments. This publication is the second edition of Microbial Enzymes and Biotechnol­ ogy which was originally published in 1983. In this edition the editors have attempted to bring together accounts (by the relevant experts) of the current status of the major areas of enzyme technology and specifically those areas of actual and/or potential commercial importance. Although the use of microbial enzymes may not have expanded at quite the rate expected a decade ago, there is nevertheless intense activity and considerable interest in the whole area of enzyme technology. Microbial enzymes have been used in industry for many centuries although it is only comparatively recently that detailed knowledge relating to their nature, properties and function has become more evident. Developments in the 1960s gave a major thrust to the use of microbial enzymes in industry. The commercial success of alkaline proteases and amyloglucosidases formed a bed-rock for subsequent research and development in the area.