to treat many problems (one-dimensional, etc.) in elegant form, the statistical interpretation of the principle of duality and the uncertainty principle of Heisenberg, and the study of discrete and continuous spectra representation of wave functions. Of particular interest is the chapter devoted to linear operators in Hilbert space and the vectors associated with dynamical observables following Dirac's ideas (bra and ket vectors) and the theory of representation of such quantities in matrix form, thus building a general mathematical formalism of quantum mechanics, usually left out in a first course, and the unification of Schrodinger's and Heisenberg's descriptions of quantum phenomena. The last third of the book deals mainly with the solution of Schrodinger's equation in three variables including such systems as the hydrogen atom, two-body problems, and scattering problems by various potential fields. The concluding chapter contains a detailed analysis of the harmonic oscillator in terms of matrix representation theory. In order to make the book self-contained, several mathematical appendixes are included with the view of facilitating the mathematical parts of the book. A good feature of this book is the inclusion of carefully selected problems not only illustrating the theory but also complementing the material of the