This textbook is meant for students who have had some prior exposure to quantum mechanics and want to move to the next level. It aims to support those who are a little behind while providing a new perspective for more advanced students. Covering material for a two-semester or three-quarter course, it offers a comprehensive background for further specialized and advanced studies in atomic, nuclear, particle, and condensed matter physics. Since some prior exposure to quantum mechanics is assumed, the most basic topics are treated briefly but with a higher perspective. The book begins with Mathematical Foundations and Basics of Quantum Mechanics. A lot of interesting physics can be explained with One-Dimensional Problems. Subsequent chapters delve into Angular Momentum, Quantum Problems in Higher Dimensions, and Identical Particles. The text then introduces Approximation Methods for Time-Independent Problems, as well as Time-Dependent Quantum Mechanics. The final chapters explore advanced topics, including Electromagnetic Radiation, Scattering Theory, and Relativistic Quantum Mechanics, ensuring a comprehensive understanding of the subject.