The good things about this book are the index, maps, and descriptions of museums and background information on a myriad of sights, accommodations and restaurants. The weaknesses are that some maps are not totally accurate, such as street name misspellings which can be frustrating, nor are the maps detailed enough at times, and that the book is rather heavy when you are toting it around Greece in a backpack.
I took it with me on a two week trip to Greece. I traveled very loosely, meaning I was never sure where I might end up. So, this book was great to have as it covers just about every possible place in Greece you could be. I did spend time in a village or two that were not described, but the main surrounding areas were, so the text was very useful nonetheless.
I used some of the phone numbers listed throughout the book and they worked fine. The color pages are filled with great information that enhance your experience for those of us not too informed about Greece and its culture. The list of interesting sights to see at each place is great as it saves you time trying to ask around locally or find such information on your own when you are pressed for time and exhausted.
Overall, this book is a terrific resource and very comprehensive. I do not think you can be too disappointed with this book, especially if you have never been to Greece before or are a novice traveler. I would recommend buying a set of detailed maps of Athens, Nafplion, or cities you intend to explore before you leave. Call the numbers or visit the websites in the book regarding metro and bus information before you go too. Most people in major cities in Greece speak enough English and/or French to help you over the phone, or at least, that was my experience.