So far I have three other books on Symmetry, Group Theory and its applications in chemistry. You can follow each link to see them. This book is quite different than the other ones. In addition to basics of symmetry and group theory, this shows the mathematics behind the theory. So, in this book you will find long proofs, equations and theorems. You can skip those parts though. But, I think it is a very good book for a graduate level course or for someone who is interested in the math behind the group theory. But, knowing this, the author actually put all the math after each chapter. So, you can still use this book and once you learn the application, you can read the math to realize how the theory is derived.
This book also has one of the best prefaces I have read:
"Finally, a word of encouragement to those who are frightened by mathematics. The mathematics involved in actually applying, as opposed to deriving, group theoretical formulae is quite trivial. It involves little more than adding and multiplying."