This book is very useful for UG/PG students of sciences and engineering. As reflected by its title "Basic of Quantum Mechanics", this book provide a framework for understanding basic concept of the quantum physics related to atoms and nuclei. This book has been written in a specific way so that it leans toward concept and related problems. So that student can learn at the early stage by a conceptual framework. The purpose of this book is to develop skills to simplify the concepts and problems of quantum mechanics. Perhaps the facing and solving the various problems of quantum mechanics gives us the better sense of understanding quantum mechanics. Here all problems which we have introduced are also taken from different types of text books and from exams like JEST, TIFR and CSIRNET/JRF to provide you the deep conceptual knowledge based on quantum mechanics. The approach to solve the questions which we have posed in this book will be more heuristic than formal and theoretical. In addition to providing a more empirical understanding of quantum mechanics, We hope that such an approach will make some of the mysteries of the theory more palatable perhaps will help to dispel some of the intractable quantum conundrums.