If you want to know which are the best known and interesting sites in an area you are visting, you cannot go wrong with this book.
It does not contain a comprehensive list and is fairly brief on many of the sites, but it will give you some ideas of places to visit and give you a bit of history behind them. If you are an avid amature historian then this book will be far too limited for you, if you are just interested in visiting a few ancient sites when on holiday then this book is perfect.
The only downside is that the writer puts one or two too many of his own opinions in rather than just giving the facts, ammusing in places, annoying in others.