The back cover says that it is "The handbook of Byzantine art for lay readers and specialists." As a lay reader (though I have read rather extensively about other periods in art and history), I did find it about one level above what I would expect from an introductory text. For example, the author on numerous occasions would go into some detail to explain the dating of a particular object, rather than use that space to describe, for example, its artistic style, or how the object (or others like it) was used or experienced by the people of that period in history. In part for that reason, I did not find this "brisk" reading as one reviewer put it.
The back cover also says that the author overturns the myth that Byzantine art (BA) remained constant. He does indeed go into great detail to show how BA of a given period was the product of a variety of factors, and how a given piece of art was different. But, again for a lay person, what is salient is how so much of BA was in fact fairly consistent in style and subject matter, and for so long, due its spiritual function. For my money, I would have liked to read at least as much about its continuity as about how much it changed.
There was also no map in the book, even though it is about art in many different countries.
And finally, although he organized his chapters chronologically, he roamed pretty freely with the art he was discussing, such that he regularly went into things, at length, that chronologically belonged to a previous or forthcoming chapter.
All that said, I did learn a lot from the book, and would recommend it to anyone with more than a beginner's knowledge of this period in art history. (You can get that beginner's knowledge by first reading Wikipedia's entries on 1) Byzantine art, 2) Icons, and 3) the Byzantine Empire.)