Among its features, the book:
* challenges the ethical framework inherited from the Judeo-Christian tradition
* offers a new appreciation of the ancient Greek moralists
* provides clearly-written, readily-grasped text
* develops material in such a way as to stimulate discussion
The book is certainly "readily-grasped"; everything else about this summary is false. It is not clearly written. Particular sections are, but trying to figure out the flow of the argument of this book is immensely difficult. I see nothing particularly new about its appreciation of ancient Greek moralists (and it only really considers Aristotle, anyway). He doesn't do any real challenging of anything, unless you call casting vague aspersions challenging. The text does not seem to have anything particularly conducive to discussion; most of it is far too vague, and, except for some shock-value statements (e.g., rejecting egalitarianism), there's not much even to get a buzz out of a hornet's nest. It isn't even clear that his thesis is remotely right; he leaves out the the Scholastics, who surely need to be considered if you're considering how we changed from a Greek view of ethics to the one we have today. His discussion of Stoicism hardly rises above caricature; and he doesn't discuss it nearly enough given that the Stoics appear to throw a wrench in the works of his view that the rise of an ethics of duty is due to the Church (his discussion of the Church is even more vague and caricatured).
I find it rather disturbing. Philosophy is, to be sure, a much more rough-and-tumble, slippery discipline than most other disciplines; we need to be a bit more flexible in our approaches than is, perhaps, entirely sane. But were an equivalent of this book published in another discipline it would, I think, rightly be laughed out of court. I find the book almost childish; and I tend to be a very sympathetic reader, willing to give authors the benefit of the doubt. Perhaps I'm missing something....