This is a comprehensive and easy to understand text. It covers all the fundamental stages of compiler design, with plenty of explanation (both practical and theoretical). It doesn't exhaustively cover every conceivable topic, but it does leave you with a good taste of what's involved. Of course, it is not a book for beginning programmers, and there are very few code examples. Judging by the comments of some reviewers, I would suspect that they gave poor reviews because they lacked the prerequisite background (familiarity with a good HLL like C, data structures, mathematical background etc). As with any 'advanced' topic in computer science, there is quite a lot expected from you. Upon first reading, some topics occasionally seem overwhelming. Welcome to Earth. This is where your library card comes in. Do a little research and then come back to this text; you'll find that it is well organized and extremely clear. If you want a cookbook this book isn't for you. If you want a solid understanding of compiler fundamentals then this book is your best bet.