A classic advanced textbook, containing a cross-section of ideas, techniques and results that give the reader an unparalleled introductory overview of the subject. The author gives an integrated presentation of overall theory and its applications in, for example, the study of groups of matrices, group representations, and in settling the problems of Burnside and Kurosh. Readers are also informed of open questions. Definitions are kept to a minimum and the statements of the theorems are sharp and clear.