This really is the one volume of Smith that everyone needs. The excerpts from Wealth of Nations are generous, but what really matters is how the volume puts it all in context. First, Heilbroner rightly includes a great deal of Smith's Theory of Moral Sentiments. Second, Heilbroner's selections are designed to give one a sense of the entirety of Smith's Theory of Moral Sentiments and Wealth of Nations; so not only does he include significant portions of these books; Heilbroner also does a nice job of summarizing those parts of Smith's texts that he is omitting. The selections from Smith's letters, the Lectures on Jurisprudence, and his writings on astronomy are welcome additions, too, though these are fairly short. This is a Greatest Hits Collection. There are a few favorite b-sides, but no deep cuts.
One can see here the origins of contemporary thinking about economics. But one also sees a figure who is a great deal more complicated than conservative ideologues would have us believe. Smith has a complex moral philosophy; a view of history akin to that of Marx (predating an inspiring it); and the beginnings of an understanding of capitalism, which is famous for emphasizing the wonders of a market economy but which also -- surprisingly, to those used to Smith-the-free-marketeer -- evinces a critical perspective on markets.