The book 'A Textbook of Organic Chemistry' was first published 40 years ago. Over the years it has become students' favourite because it explains the subject in the most student-friendly way and is revised regularly to keep itself updated with the latest in research. This edition presents the modern-day basic principles and concepts of the subject as per the CBCS of UGC guidelines. Special emphasis has been laid on the mechanism and electronic interpretation of reactions of the various classes of compounds. It provides a basic foundation of the subject so that based on these, students are able to extrapolate, predict and solve challenging problems.