I bought this book at a bookshop in Beijing after having all but worn out my friend's copy -- and it has been worth every penny.
Words and phrases are helpfully arranged by topic. Cultural tips are both witty and informative. There is a brief explanation of grammar (which is all that is needed; Chinese grammar is very simple), as well as a brief explanation of pronunciation. The pronunciation guide, while among the best in phrasebooks, is not nearly sufficient for learning the precise pronunciation that is necessary for communicating in Chinese. If you've never been to China, and plan on being able to communicate, however modestly, you'll want to get started on pronunciation right away. A book with an audio aid would be better for this, but there is really no substitute for a real-life Mandarin speaker. All words are romanized for the reader's convenience according the pinyin system, which is slightly confusing at first, but is generally the most helpful system in the long run. Characters are included so that the distressed traveler (and there will be times of distress if you travel in China -- nothing to worry about, but still a fact of life in the Middle Kingdom) can simply point to the characters if all else fails.
In all, this phrasebook is a nonpareil among Chinese phrasebooks. Its limitations simply reflect the limitations of phrasebooks in general, though the authors have done a remarkable job of making it as useful as possible. Whether you know no Mandarin at all, or have a rudimentary knowledge of it and want a safety net, this book is the one to buy.