The third edition of the book is thoroughly updated and presented in a new two-colour format. The book presents a detailed and authoritative exposition of the basic principles and applications of biochemistry. It focuses primarily on clarity of the fundamental concepts and explains them according to the need of undergraduate medical students. The organization of content in this book is such that it provides the reader with a logical sequence of events that aids learning.More emphasis in this edition is to systemize presentation and make reading soothing and pleasurable by deleting redundant details, adding new text and figures, improvement of earlier figures, supplementing text with easy to comprehend flowcharts, without changing basic framework of the book. Each chapter ends with clinical cases and the related questions, which evokes yet another method of active learning rather than didactic methods of imparting knowledge. Key points have been highlighted and boxed at the end of each topic for quick revision of the core concepts. This book comes with a free companion website which contains self-assessment exercises, detailed case discussions related to the clinical cases given inside the book, glossary and various other features for enhanced learning.