This book is an introduction to molecular genetics and is designed primarily for Post graduate students and Research scholars. The book contains three types of information. The main part of each chapter is the text. Following each chapter are references and problems. References are arranged by topic, and one topic is “Suggested Readings”. The additional references cited permit a student or researcher to find many of the fundamental papers on a topic. Some of these are on topics not directly covered in the text. Because solving problems helps focus one’s attention and stimulates understanding, many thought-provoking problems or paradoxes are provided. Some of these require use of material in addition to the text. Solutions are provided to about half of the problems. Although the ideal preparation for taking the course and using the book would be the completion of preliminary courses in biochemistry, molecular biology, cell biology, and physical chemistry, few students have such a background. Most commonly, only one or two of the above-mentioned courses have been taken, with some students coming from a more physical or chemical background, and other students coming from a more biological background. An auxiliary objective of this presentation is to help students develop an appreciation for elegant and beautiful experiments. A substantial number of such experiments are explained in the text, and the cited papers contain many more.