The book discusses the divide between rich and poor nations that came about as a result of the Industrial Revolution in terms of the evolution of particular behaviours that Clark claims first occurred in Britain.

Prior to 1790, Clark asserts that man faced a Malthusian trap: new technology enabled greater productivity and more food, but was quickly gobbled up by higher populations.

This process of "downward social mobility" eventually enabled Britain to attain a rate of productivity that allowed it to break out of the Malthusian trap.

For example, Kuznicki from the libertarian Cato Institute stated, in a generally positive review, that "his explanation begins to look very ad hoc when considering the last few decades".

[12] In this article, Clark argues, using an estimate of heritability of wealth derived from his data, that "the wealthy in pre-industrial England had to be different in personality and culture from the poor".

He therefore suggests that A Farewell to Alms' hypothesis of how statistically significant genetic differences between the rich and the poor might have arisen "is a very real possibility".