The application of enzymes or whole cells (fermentatively active or resting; microbial, plant, or animal) to carry out selective transformations of commercial importance is the central theme of industrial biocatalysis. Traditionally, biocatalysis has been in the domain of the life scientist or biochemical engineer. However, recent advances in this field have enabled biocatalytic processes to compete head on with, and in some cases out­ perform, conventional chemical processing. Chemo-biocatalytic systems are being developed thereby combining the most attractive features of bio­ catalysts, namely high specificity, with those of chemical catalysts, such as high reactivities and wide substrate specificities. Hence, synthetic chemists and chemical engineers are now beginning to use biocatalysts as highly selective reagents in chemical synthesis and processing. This book is about biocatalysts and their past, present, and potential applications in the food, pharmaceutical, and chemical industries. The concept of the book did not emanate from a meeting. Rather, it is a compila­ tion of selected examples where biocatalysis either has already made a significant impact in the aforementioned industries, or has the potential to make a substantial contribution. I have been fortunate to have assembled contributions from world-class researchers in the field of biocatalysis. Their timely contributions are sincerely appreciated.