'The authors should be recognised for their efforts to present a mathematically rigorous introduction to Quantum Mechanics (QM) in a form that has broad appeal; there are not many introductory QM texts that would cover, for example, decoherence. I think many educators would appreciate this book, especially those interested in courses that combine science and philosophy.'Contemporary PhysicsApart from providing a lucid introduction to the mathematical formalism and conceptual foundations of quantum mechanics, we explain why the laws of physics have the form that they do. In addition, we present a new and unique look at the quantum world, steering clear of two common errors: the error of the ψ-ontologists, who reify a calculational tool; and the error of the anti-realists, for whom physical theories are simply devices for expressing regularities among observations.The new edition of this acclaimed text adds around 200 pages on a variety of topics, such as how the founders sought to make sense of quantum mechanics, Kant's theory of science, QBism, Everettian quantum mechanics, de Broglie-Bohm theory, environmental decoherence, contextuality, nonlocality, and the paradox of subjectivity — the curious fact that the world seems to exist twice, once for us, in our minds, and once by itself, independently of us.