This is a great book. The format is a bit odd(chapters are short) and one could wish for more but one of the better books on group theory as it generally provides philosophical motivations rather than just throwing definitions at you without any background. Probably would make a great introduction as long as one had the proper foundations. Definitely worth the money but it might not be the best to learn from due to the lack of in depth instruction but if one already has some idea of what is going on then it will be effective. It is about my 4th book on group theory and If found that it added some new insights and solidifications that I did not get from the previous books but it is not as rigorous as a typical graduate level textbook. It's worth having.