That is the new book by Greg Woolf. Could it now be the best single-volume introduction to the history of ancient Rome? It is conceptual yet avoids the pitfalls of overgeneralizing, a difficult balance to strike. It also has a superb (useful rather than exhaustive) bibliography. A good measure of books such as this is whether they induce you to read or order other books on the same topic and this one did.
A sure thing to make my “Best Books of 2012″ list.