Summary of this review: You'll find yourself getting interested in, and understanding, concepts, very easily, but if you're an advanced reader you'll often find (at the end of the chapters) that the more advanced topics/problems have been glossed over.

If this is your assigned course textbook, you're lucky. If this is NOT your assigned textbook, USE it as your guide. It makes topics simpler and more intuitive. The way Sipser ropes down exotic theorems into straightforward, understandable logic is almost magical. The book scores in most areas: smoothness of flow, ease of understanding, order of presentation, motivational cues, and thoroughness in the areas covered.

The problem with the book is in the number of topics covered, and in the number of examples. There are not sufficient examples in some cases, and not sufficient material in some cases. This is a small textbook. At the end of each chapter, Sipser often glosses over the more advanced issues. If doing a thorough study, one will frequently need a more complete reference.

This will, of course, not be a problem if your course does not go beyond what is covered here: Finite Automata, Turing Machines, the relationship between the classes of languages, reducibility, and complexity theory.