What does quantum mechanics tell us about the key model physical systems of nature? The author of this highly regarded text explores this question in a conceptual manner, fusing mathematical and philosophical elements to present physical imagery that closely parallels the mathematics. Beginning with an overview that discusses the premise and design for the study, the text proceeds with an examination of the classical quantum bead on a track: its states and representations; its measurement spectra as operator eigenvalues; the harmonic oscillator: bound bead in a symmetric force field; and the bead in a spherical shell. Other topics include spin, matrices, and the structure of quantum mechanics; the simplest atom; indistinguishable particles; and stationary-state perturbation theory. Geared toward upper-level undergraduate students in physics, this refreshing and instructive text requires the following background: a freshman-year survey course in physics, a first course in classical Newtonian mechanics, and a grasp of mathematics that encompasses integral calculus, vector analysis, differential equations, complex numbers, and Fourier analysis.