Nuclear Physics has been occupying continuously an important place in any University course in physics at the graduate and PG levels in India. The main purpose of A Text Book on Nuclear Physics is to give a concise account of the fundamentals of the physics of the nuclei and particles and applications of nuclear energy. Its coverage extends the conventional aspects of the subject, because it has become very evident in recent years that much of the great body of knowledge of nuclei, acquired several decades ago, is highly relevant to other field such as solid state, modern spectroscopy, chemistry, biological / medical physics and technology of power production. In a book of moderate size it is not possible to give a comprehensive treatment, in depth, of the whole of subatomic physics, for the student community at the degree level. However, I have tried to add my experience of teaching, 4 credit semester courses, on the subject a few years during my tenure (1971 - 2000) to the M.Sc. students at the Department of Physics of the University of Kerala, Kariavattom campus, Thiruvananthapuram. My experience in research in the field of Mossbauer spectroscopy has certainly an impact in the quality of the contents of the book. Further, as an author of four books, I could prepare this book in its own uniqueness for instance providing student friendly features. I have incorporated a good deal of Worked out Examples with solutions at appropriate places and Review Questions including their answers at the end of each Chapter. Outline solutions are deliberately avoided so as to reduce the volume of the book. I have kept the mathematics as simple as possible. I assume knowledge of the basics of special relativity and basic quantum mechanics The many bibliographic references have been arranged in alphabetical list to enable students as well as faculty, for their academic references. The present book is designed rather to meet the needs of the academic community who wishes to adopt the whole or parts of the book as a text for the prescribed syllabus of any course containing nuclear physics. It is hoped that the book will be of interest to those whose work lies inter-disciplinary fields, for example health physics, industrial physics, and related fields.