Textbook of Biotechnology, 5th edn., has evolved considerably since the first edition was published in October, 2004, with respect to both structure and content. The main objective has been to conform as far as possible to the recommendations of the expert committees of both University Grants Commission and Department of Biotechnology, Government of India, who had developed the curricula. Hence, the sequence of the chapters in the textbook has been kept exactly as the sequence in which the expert committees had arranged the topics in the recommended Biotechnology curriculum. A broad-spectrum of subjects necessary to understand and teach Biotechnology has been covered and each chapter is written in an in-depth and up-to-date manner.