'This excellent book contains an introduction to the theory of abstract groups, Lie groups and their representations combined with applications of this theory in physics ... a cohesive presentation of physics and mathematics.' A. L. Onishchik, Zentralblatt fur Mathematik 'The book is a very good example of a bedside or coffee table book. One can dip into it for fun, keep on reading, and end up learning something useful. I raided it last spring to add spice to my introductory course on 'Lie Groups' at Cambridge.' C. B. Thomas, Bulletin of the London Mathematical Society 'This is a remarkable book ... The author shows how physical considerations lead naturally to mathematical notions and their investigations, and how mathematical achievements influence the development of physics ... I can strongly recommend the book.' European Mathematical Society Newsletter