This book has been written to introduce readers to group theory and its ap- plications in atomic physics, molecular physics, and solid-state physics. The first Japanese edition was published in 1976. The present English edi- tion has been translated by the authors from the revised and enlarged edition of 1980. In translation, slight modifications have been made in. Chaps. 8 and 14 to update and condense the contents, together with some minor additions and improvements throughout the volume. The authors cordially thank Professor J. L. Birman and Professor M. Car- dona, who encouraged them to...