The structure of much of solid-state theory comes directly from group theory, but until now there has been no elementary introduction to the band theory of solids which adopts this approach. This book provides such an introduction, employing only the simplest and most basic of group theoretical ideas, and emphasizing the significance of symmetry in determining many of the essential concepts used in the subject. Topics include: the free-electron model, the reciprocal lattice and the Fourier series, space group representations, phonons and conductivity, and surface and impurity states, among many others. Numerous problems are included which enable the reader to apply the major ideas and to complete some parts of the treatment. Students and researchers in chemistry and other physical sciences will find the book the introduction to band theory they have been waiting for.