If you are traveling as a tourist to Syria (as I recently did), this is THE book to read: an intelligent layman's guide to the architectural (above all archaeological) wonders of Syria, which are the primary reason for tourist visits there.
It is one of only two texts in English which occupy the wide gap between, on the one hand, a cursory "Lonely Planet" guide approach (I much value "Lonely Planet" but, let's face it, such tourist manuals do not delve very deeply), and--on the other hand-- a mind-numbing plethora of narrowly focused, deadly dull, and hard-to-get academic monographs on small slices of Syrian phenomena.
The only book currently competing with Ball's to fill this gap is "The Monuments of Syria: A Guide" by Ross Burns. The latter is a Baedeker-style encyclopedic gazeteer of most/all Syrian archaeological sites; its broad scope means you get descriptions of many minor sites you are unlikely to visit, but not always as much information as you would like on the major sites you will see. We should be immensely grateful to Burns for his effort, but it is most appropriate for those planning to spend more than two weeks or so in Syria and to go beyond all the major sites. For those spending 2 weeks or less, Ball's book is the one for you if you only want to buy one text. (But you still might well consider Burns' book as a very useful adjunct.) Besides the virtues of its individual site descriptions, Ball's text offers very helpful and concise introductory overviews of the history and geography of Syria, and above all a broad survey of the various architectural trends and styles one will see at the different sites.
A word about the author. Warwick Ball is a long-time Middle Eastern archaeologist (with much experience in Syria and Jordan) who retired his trowel some years ago to found a blue-chip tour company (with focus on the Middle East) headquartered in Scotland, where he now lives. I serendipitously encountered him and his book at a lecture he gave on Afghanistan at Washington, DC's Smithsonian Institution in early 2010.
A couple minor nits re the book. Ball can be repetitive in harping on certain points, especially. his all too oft stated observations which link virtually any cubist structure in Syria back to early South Arabian prototypes. He is a "booster" on Syria (as you would expect from one who spent a lot of time and effort there), so you need to discount a bit his more enthusiastic claims about everything Syrian and some of the sites there. That said, I can tell you the country IS worth visiting and does have some "drop dead" archaeological sites and is getting a lot of Western (above all West European) tourism nowadays. Finally, the maps Ball employs for the book are borrowed and not designed specifically to support his text, so they are not entirely satisfactory. Above all, if you contemplate wandering around the souks (markets) of old Damascus, you're going to need a more detailed map than this book provides if you don't want to get hopelessly lost.
But these are minor criticisms which should not obscure the great virtue of this book: it almost single-handedly fills a need for those bound for Syria, and it does so very well.