This introductory course on quantum mechanics is the basic lecture which precedes and completes the author's second book Advanced Quantum Mechanics. The new edition is again up-to-date and has been revised. The book meets the students' needs by giving all mathematical steps, worked examples with applications throughout the text, and many problems at the end of each chapter. It contains nonrelativistic quantum mechanics and a short treatment of the quantization of the radiation field. Besides the essentials, topics such as the theory of measurement, the Bell inequality, decoherence, entanglement and supersymmetric quantum mechanics are discussed. It includes helpful appendices on Green's functions, canonical and kinetic dynamical variables, and eigenfunctions.