This book is written with students of biotechnology firmly in mind. It has arisen out of author's own experience of teaching in the biological disciplines. The book which takes the students on from his basic knowledge of biochemistry, microbiology and molecular metabolism, the growth and culturing of micro-organism, genetic manipulation and biocatalyst technology. The book is divided into several sections, the first dealing with basic principles and then with a range of illustrative examples of practical biotechnology. This is the order in which the book itself should be used, but its contents were actually determined by working in reverse order: the book start from a range of actual examples of productive biotechnology. It follows that the typical scientist or engineer, and in particular the newly graduated scientist for whom this book is primarily intended, will find some of the basic principles quite familiar, while others fall quite outside his or her past experience. This text is designed to assist students and industrial people who are having to or who will have to grapple with areas of biotechnology. Because of the wide range of the potential subject matter, the author have had to be selective. The very comprehensive coverage of biotechnology provided by this book can provide the means for the improvement of existing industrial processes and can provide the starting points for new industries, for the manufacture of novel products and for improved processes for management of the environment.