Simple enough for students, comprehensive enough to serve as a reference for professionals. Subjects include formalism and its interpretation, an analysis of simple systems, symmetries and invariance, methods of approximation, elements of relativistic quantum mechanics, much more. "Strongly recommended." — American Journal of Physics.
Here's a sample of other books in this Dover category
Quantum Theory of Many-Particle Systems by Alexander L. Fetter, John Dirk Walecka Self-contained treatment of nonrelativistic many-particle systems discusses both formalism and applications in terms of ground-state (zero-temperature) formalism, finite-temperature formalism, canonical transformations, and applications to physical systems. 1971 edition.
Weak Interactions and Modern Particle Theory by Howard Georgi This high-level, rigorous, and technical treatment was written by a distinguished teacher and researcher. Equally valuable as a text for advanced undergraduates and graduate students and as a reference for professionals. 1984 edition.
Applications of Group Theory in Quantum Mechanics by M. I. Petrashen, J. L. Trifonov This advanced text explores the theory of groups and their matrix representations. The main focus rests upon point and space groups, with applications to electronic and vibrational states. 1969 edition.
Sources of Quantum Mechanics by B. L. van der Waerden 17 seminal papers, published from 1917 to 1926, develop and formulate quantum theory. Contributors include Einstein, Bohr, Born, Van Vleck, Heisenberg, Dirac, Pauli, and Jordan. An introduction provides historical perspective.
Problems in Quantum Mechanics by I. I. Gol’dman, V. D. Krivchenkov Geared toward advanced undergraduates and graduate students, this challenging book contains a comprehensive collection of problems in nonrelativistic quantum mechanics, with answers and worked-out solutions to each problem. 1961 edition.
Stochastic Methods in Quantum Mechanics by Stanley P. Gudder This introductory survey of stochastic methods and techniques in quantum physics, functional analysis, probability theory, communications, and electrical engineering also serves as a useful and comprehensive reference volume. 1979 edition.
Introduction to the Quantum Theory: Third Edition by David Park Geared toward upper-level undergraduates and graduate students, this self-contained first course in quantum mechanics covers basic theory and selected applications and includes numerous problems of varying difficulty. 1992 edition.
The Fundamental Principles of Quantum Mechanics: With Elementary Applications by Edwin C. Kemble Hailed by Linus Pauling as "excellent," this graduate-level treatment interweaves applications of theory with development of mathematical structure. Topics include wave packets, two-particle central-field problem, many-particle problem, much more. 1937 edition.
Problems of Atomic Dynamics by Max Born The Nobel Laureate discusses the foundations of quantum theory in two lectures, one on the structure of the atom, the other on the lattice theory of rigid bodies.
Group Theory and Quantum Mechanics by Michael Tinkham Graduate-level text develops group theory relevant to physics and chemistry and illustrates their applications to quantum mechanics, with systematic treatment of quantum theory of atoms, molecules, solids. 1964 edition.