These are the lecture notes from a twosemester graduate course and a twosemester undergraduate course taught by the author. The lectures are arranged in a logical manner and reflect the informality of the classroom. Each topic is explained with several examples so that the ideas develop naturally, which is immensely helpful to students. The book is selfcontained; most of the steps in the development of the subject are derived in detail and integrals are either evaluated or listed when needed. The motivated student can work through the notes independently and without difficulty. The book is suitable for graduate students in mathematics or advanced undergraduates in physics interested in an introduction to quantum mechanics. A publication of Hindustan Book Agency; distributed within the Americas by the American Mathematical Society. Maximum discount of 20% for all commercial channels. Readership Graduate students and research mathematicians interested in quantum theory. Table of Contents  Review of classical mechanics
 Review of essential mathematics
 Basics of quantum mechanics
 Simple applications of Schrodinger equation
 Harmonic oscillator
 Symmetries and their consequences
 Angular momentum
 Schrodinger equation in higher dimensions
 Hydrogen atom
 Approximate methods
 WKB approximation
 Stationary perturbation theory
 Time dependent perturbation theory
 Spin
 Scattering theory
 Relativistic one particle equations
 Path integral quantum mechanics
