"No wonder that after he read Malthus, Carlyle called economics 'the dismal science'..."I think there are lots of people who still accept this explanation of how economics became "the dismal science;" I did until a few years ago. However, the true story is much more interesting. It is told by Levy and Peart here. A summary of that view is on Wikipedia here. Which is more interesting, Heilbroner's view, or Levy and Peart's view?
For a book in its seventh edition, there are some errors that should not be there. On page 85-6 Heilbroner writes:
Mention of Maria Edgeworth warrants an additional word. The daughter of an economist...."If she was a friend of Malthus and Ricardo, then her father must have been one of the first economists, as he was only 20 years younger than Smith. However, Heilbroner is confusing her father with her nephew, Francis Ysidro Edgeworth. That mistake might be excusable in a first edition, but not in the seventh of such a widely-read book.
Then there are sentences that stop an economist, though the noneconomist probably sees nothing at all wrong with them. How about this (on 49) in his discussion of Smith and Quesnay:
"To see that labor, not nature, was the source of "value," was one of Smith's greatest insights."