An ideal undergraduate textbook, as well as an excellent reference book for the more advanced student. Enough detail for the for the beginner without becoming overwhelming, and good for quick references or to reorient yourself with a particular period if you are an aspiring Byzantinist. I wrote a senior thesis paper using this book (in conjunction with Norwich's 3 volume History of Byzantium) as my central, general text, and was more than satisfied with the information I was able to glean from it. It is a starting point to be sure, but a very, very good one.

Full Disclosure: I'm going to be Dr. Gregory's graduate student in the fall (but I haven't studied with him at the time of writing this review!);I suppose you should keep this in mind when reading this review :)

P.S.: Be sure to get the updated second edition of this book rather than the first. Several elements have been upgraded, and it is well worth the extra money. ( )