This introduction to quantum mechanics attempts to stick to reality-based interpretations to the extent possible. The preface presents the author's philosophy of physics, which is essentially a call for eclecticism and a realization of the nature and limits of physical concepts and theories. Chapter 1 starts with a review of the pre-1925 quantum achievements of Planck, Bohr, and Sommerfeld, including Einstein's discovery, well before wave mechanics came on the scene in 1925, of the photon concept and its implication of wave-particle duality. The more straightforward consequences of wave mechanics are then covered. Chapter 2 further develops ideas of wave mechanics, and presents the Schrödinger equation with a number of simple applications. The chapter puts appropriate emphasis on the nature of the quantum state and the importance of state preparation, and concludes with a review of quantum interpretations from 1925 up to the present. Chapters 1 and 2 alone can serve as a lower-level introduction to the subject. Chapters 3 to 7 present many of the standard results of quantum mechanics. Chapter 3 concludes with the GRW collapse theory, and Chapter 4 with the role of decoherence in the measurement process. The hydrogen atom and Thomas precession are thoroughly treated in Chapter 6. Chapter 8 delves into time-dependent perturbations and transitions with a careful development of Fermi's Golden Rule. Few quantum mechanics texts consider the classical roots of the Schrödinger equation, but this interesting task is carried out in Chapter 9. Chapter 10 is devoted to hidden variables, non-locality, and Bell's theorem, and Chapter 11 builds on the work in Chapters 9 and 10 to give a short introduction to David Bohm's "ontological" interpretation. The book concludes with Dirac's relativistic equation for the electron and its prediction of the ever-elusive "zitterbewegung." The prerequisites for most of the book are good backgrounds in calculus and modern physics. A familiarity with vector analysis and linear algebra would also help. About the Author: Frank Munley earned a Ph.D. in physics from Johns Hopkins University with a thesis on the effect of critical slowing down on Mössbauer spectra. He worked in aviation safety, which included authoring a study on commuter airline safety using a record of departure-based statistics he constructed. This work led to a tightening of federal regulations. He also worked in economic statistics, devising models of asset lifetime estimation. Frank taught physics for 26 years, the last 21 at Roanoke College, which afforded him the opportunity to teach a course on the nuclear arms race prior to the end of the first Cold War. His main interest in physics focuses on improvements in the physics-major curriculum and the philosophy of physics.