"The subject matter is presented in a very thorough way. Detailed and clear proofs are given for (almost) all results. The material is very well organized: definitions, results, and their interrelations fit together perfectly. The book is especially attractive to students with a background or interest in computer science. On the other hand, students who already have a background in abstract algebra can benefit greatly from this book by skipping some parts where algebraic theory is introduced. The suitability of the book for self-study is greatly enhanced by a wealth of exercises and examples that are provided. Last but not least, the book is very well-written, and it is a pleasure to read.
Gregor Kemper, Mathematics of Computation

"It’s a pleasure to find a book that is so masterful and so well written that it has all the hallmarks of a classic. This is such a book.This is a truly magnificent text, deserving of a place on the shelves of any mathematician or computer scientist working in these areas."
Alasdair McAndrew, Computing Reviews