This textbook is written as a basic introduction to Quantum Mechanics for use by the undergraduate students in physics, who are exposed to this subject for the first time. Providing a gentle introduction to the subject, it fills the gap between the available books which provide comprehensive coverage appropriate for postgraduate courses and the ones on Modern Physics which give a rather incomplete treatment of the subject leaving out many conceptual and mathematical details. The author sets out with Planck’s quantum hypothesis and takes the student along through the new concepts and ideas, providing an easy-to-understand description of core quantum concepts and basic mathematical structures. The fundamental principles and the mathe-matical formalism introduced, are amply illustrated through a number of solved examples. Chapter-end exercises and review questions, generally designed as per the examination pattern, serve to reinforce the material learnt. Chapter-end summaries capture the key points discussed in the text. Beside the students of physics, the book can also be used by students of chemistry and first-year students of all branches of engineering for gaining a basic understanding of quantum mechanics, otherwise considered a difficult subject.