Since the publication of the first edition over 35 years ago, Quantum Physics has been one of the standard quantum mechanics texts for undergraduate physics majors. Its hallmarks are clear, concise exposition and a balance of theory and applications. In the 3rd Edition, the author has made numerous changes—based on feedback from teachers and students—to enhance the book's strengths. One of the author's important goals has been to offer teachers and students a textbook that is manageable in one semester. However, recognizing that some teachers like to go into more depth on certain topics, he has developed a web site where more detailed presentations can be found.