Rating: 
Summary: first edition is a classic, the second one unremarkable
Review: The first edition is one of the best book in its field. A classic. A reference for many advanced courses in computer theory.Sadly, the second edition misses a great deal of the first edition. Many chapters were removed. Important lemmas and theorems are missing. I would gladly exchange my second edition for the first one, if it wasn't out of print. J.
Rating: 
Summary: Excellent as a reference; pathetic as a textbook
Review: There is, strictly speaking, no in-between for this book: it's either 5 stars or zero stars depending on the intended use. It's very simple: Don't use it if _____, and do use it if ____. Do NOT even THINK of buying this book: 1. If this is going to be your first brush with formal languages and the theory of computation. 2. If you need to get motivated to learn the subject, and you need that "first grasp" on it. 3. If you're taking a first course in the subject, and if you have an IQ below 130! On the other hand, You MUST buy this book: 1. If you already have some background, and you want a larger picture. 2. If you will often need an authoritative source for proofs etc. 3. If you need a reference for formalizing concepts touched on elsewhere.
Rating: 
Summary: Impressive book for deep thinking
Review: This book comes before the dragon book and delivers important
theories like Finite Automata, BNF, Context Free Grammar, Turing
machine and etc. My philosophy for better understanding of
computer is to get a complete concept of the computer theory first, then try to simulate and code it. This book gives you
a clear concept of computer theory that can drive your brain
to think what a computer is and you can dry-run your program
without a desktop computer next to you.
Rating:
Summary: Tired of finding an alternative
Review: This book is a pain to follow. The authors have assumed readers would have a certain level of background knowledge. With this book being the preferred material in most univs wouldn't they bother to make it more understandable, include a few basic chapters for the users' benefit? It doesn't take the reader from a low level and walk him up, instead it starts somwhere at the top and stays there making it very difficult for users to follow the material. The frustrating part is I have not been able to find alternatives to this book for understanding the basics.One review suggested that a person should never go near this book unless his/her IQ is 130 or above. I have an IQ of over 130 and I'm groping in the dark. Would not recommend it to anyone but would love to see posts suggesting alternatives.
Rating:
Summary: Ugh
Review: This book is an exercise in frustration. The format, which is inexcusable in a text for nonexperts, is 'Provide example, then dissect example into pieces organized by theory.' I personally find this approach very hard to follow. I would much rather have the relevant theory discussed first, then, once I know the rules, have examples. Additionally, there is a vast insufficiency of examples and exercises in this book. Repetition is learning, and to be able to leave with a functional understanding of the concepts, students need to have a variety of illustrative problems available. The exercises in this book are weak at best. Solutions to all exercises must be provided if there is to be any benefit to working through them in the first place. The fact that this book is the best available introductory text for this subject only shows that there is plenty of room for some ascendant computer science faculty to write a well written, well organized, and amply illustrated, replacement.
Rating: 
Summary: Not a good choice for your first contact with automatas
Review: This book may be an excellent reference text, but as a learning tool it is abysmal. It is confusing and takes a lot of knowledge for granted. I second earlier reviews and recommend Michael Sipser's "Introduction to the Theory of Computation" instead, which has to be one of the best books I've ever read for class.
Rating:
Summary: A reference book
Review: This is *not* a good book to use as an introduction to computation theory (CT). If you *already* know CT and look at this book, everything will make perfect sense and seem 'obvious'. If this is your first exposure to CT, then this book will seem very confusing. There are far far better books to purchase if you wish to *learn* CT, namely "Introduction to the Theory of Computation" by Michael Sipser. Once you have the basics down, you will be able to appreciate the detail of the Hopcroft book. As a reference book, however, it is very good. It is extremely concise which makes it easy to zoom in on definitions and theorems without having to wade through explanations. If you are taking a course in CT and this is the text you are using, then I suggest either getting Sipser's book or hope you have a really good prof!
Rating: 
Summary: Good, but the first edn was Great
Review: This is a good book - but as a revision of a much-revered classic of
the field, it's a bit of a disappointment. Hopcroft & Ullman wrote the classic text way back in 1969, and then
revised it in 1979. It was pretty much the standard text the world
over for an introduction to the theory of computation. But over the last two decades, more and more people have been studying
Computer science, and many of them have no time for theory and
formalism and all the 'dry stuff' .......... The authors point out that because of such reasons and also because
nowadays there's little research in the theory of computation per se,
and more in its applications, they've written a book to cater to today's
students. Which, in other words, means they've simplified the presentation, tried
to provide intuition whenever possible, given lots more examples and
done away with some of the more difficult material. This approach puts the book into direct competition with Michael Sipser's
excellent 'Introduction to the theory of computation', a contest it
cannot win, though it might be a respectable second. Almost all topics are motivated by giving examples of how they're
related to applications in the 'real world', and similar to
Sipser's 'proof idea' approach, the authors first present a topic
informally and then formally, thus gently leading the reader to
the formal proofs.
This book sets out to do pretty much the same as what Sipser's book
does, ie to provide a readable, user-friendly introduction to the
theory of computation with lots of examples and intuitive approach
to problems wherever possible, but Sipser's already done an
'optimal' job. Moreover, this book tries to be 'chatty', which i'm afraid is just
not the authors' style - the 'economy of expression', which has long
which has long been the hallmark of the legendary textbooks by
Aho,Hopcroft and Ullman, is sadly missing here. Which means that this may not be the book for you if you're pressed
for time - but on the other hand, if you want to led gently to the
proofs and results with lots of examples and motivation, then this
might be just the book for you. So all in all, it definitely worth a read - in fact, i'd say
it's still among the top textbooks around. In fact, i would suggest that you read both this and Sipser, if you
have the time. Otherwise Sipser's the better choice for most of the
part, though it may not cover all the topics you need. And if you're comfortable with a terse, concise & rigorous
presentation, then the earlier edition of this book is still
unbeatable - and you'll surely need it if you want to pursue research
in this area.
Rating:
Summary: Good, but the first edn was Great
Review: This is a good book - but as a revision of a much-revered classic of
the field, it's a bit of a disappointment. Hopcroft & Ullman wrote the classic text way back in 1969, and then
revised it in 1979. It was pretty much the standard text the world
over for an introduction to the theory of computation. But over the last two decades, more and more people have been studying
Computer science, and many of them have no time for theory and
formalism and all the 'dry stuff' .......... The authors point out that because of such reasons and also because
nowadays there's little research in the theory of computation per se,
and more in its applications, they've written a book to cater to today's
students. Which, in other words, means they've simplified the presentation, tried
to provide intuition whenever possible, given lots more examples and
done away with some of the more difficult material. This approach puts the book into direct competition with Michael Sipser's
excellent 'Introduction to the theory of computation', a contest it
cannot win, though it might be a respectable second. Almost all topics are motivated by giving examples of how they're
related to applications in the 'real world', and similar to
Sipser's 'proof idea' approach, the authors first present a topic
informally and then formally, thus gently leading the reader to
the formal proofs.
This book sets out to do pretty much the same as what Sipser's book
does, ie to provide a readable, user-friendly introduction to the
theory of computation with lots of examples and intuitive approach
to problems wherever possible, but Sipser's already done an
'optimal' job. Moreover, this book tries to be 'chatty', which i'm afraid is just
not the authors' style - the 'economy of expression', which has long
which has long been the hallmark of the legendary textbooks by
Aho,Hopcroft and Ullman, is sadly missing here. Which means that this may not be the book for you if you're pressed
for time - but on the other hand, if you want to led gently to the
proofs and results with lots of examples and motivation, then this
might be just the book for you. So all in all, it definitely worth a read - in fact, i'd say
it's still among the top textbooks around. In fact, i would suggest that you read both this and Sipser, if you
have the time. Otherwise Sipser's the better choice for most of the
part, though it may not cover all the topics you need. And if you're comfortable with a terse, concise & rigorous
presentation, then the earlier edition of this book is still
unbeatable - and you'll surely need it if you want to pursue research
in this area.
Rating:
Summary: This is the book.
Review: This is the one book that I refer to time and time again for all of my automata-theory needs. It covers all the fundamental theorems of finite-state automata such as determinization and the pumping lemma in a clear, concise manner. Excellent coverage of context-free grammars, with excursions into generative power, normalization and parsing. The book is rigorously mathematical, yet easy to understand. I came to this book fifteen years ago as a grad student after reading Lewis and Papadimitriou (which is good, but overly detailed on notation where context would suffice), used it as a professor teaching automata theory at Carnegie Mellon, and now use it as a software engineer for a speech recognition company that builds grammars.
| 
