The present book has been written to cover up the course on 'Reproductive Biology' prescribed for the biology students of different Indian Universities. The discussion is suitable for post graduate students; it provides the indispensable knowledge without which the most recent advancements over a wide front cannot be understood. The subject matter of the book is represented in the way which is best suited to the needs of our Indian students. The book presents the fundamental ideas of the 'Reproductive Biology' in simple and concise form and it gives to the students a proper background of subject and introduces them to the body of factual informations revealed by modern researches of the last two decades. The special features of this book are described as: 1) It has been written in simple and fluent language. 2) The subject matter is systematically arranged and it is fully illustrated by easy diagrams. 3) Each topic is discussed in the light of recent researches that have greatly illuminated many of the earlier discoveries on embryological phenomena by revealing the molecular basis of those phenomena. It is hoped that the teachers and students will find this book suitable.