It was felt by several teachers and the editor as well, that the sequence of the chapters in the book did not reflect the sequence in which a student ought to study the various areas to fully appreciate the different aspects of Biotechnology. Hence, the sequence of the chapters in the book was kept exactly as the sequence in which the expert committees had arranged the topics in the recommended Biotechnology curriculum. More teachers have commented on this matter since the publication of the second edition. In the third edition of the book, this anomalous practice has been discontinued and the sequence of chapters has been revised. In this edition significant revision has been carried out in the chapters on Medical Microbiology, Biophysical Chemistry, and Genomics and Functional Genomics.