Book excerpt: In learning quantum theory, intuitions developed for the classical world fail, and the equations to be solved are sufficiently complex that they require a computer except for the simplest situations. This book represents an attempt to jump the hurdle to an intuitive understanding of wave mechanics by using illustrations to present the time evolution and parameter dependence of wave functions in a wide variety of situations. Most of the illustrations are computer-generated solutions of the Schrödinger equation for one- and three-dimensional systems, with the situations discussed ranging from the simple particle in a box through resonant scattering in one dimension to the hydrogen atom and Regge classification of resonant scattering. Thoroughly revised and expanded to include a discussion of spin and magnetic resonance.