On the Principles of Political Economy and Taxation

Ricardo claims in the preface that Turgot, James Steuart, Adam Smith, Jean-Baptiste Say, Sismondi, and others had not written enough "satisfactory information" on the topics of rent, profit, and wages.

Regardless of whether the book achieved that goal, it secured, according to Ronald Max Hartwell, Ricardo's position among the great classical economists Adam Smith, Thomas Malthus, John Stuart Mill, and Karl Marx.

In his book Adam's Fallacy: A Guide to Economic Theology, economist Duncan K. Foley highlights that in the Principles Ricardo criticizes Adam Smith's treatment of the theory of value and distribution for circular reasoning, in particular as far as concerns rent, and that Ricardo considers the labor theory of value, properly understood, a more logically sound basis for political economic reasoning.

Whereas the landowning class and capitalists benefit from the lower prices, workers in contrast do not reap such benefit from the lower prices if capitalists reduce the wage fund in order to finance the expensive machinery, causing technological unemployment among workers.

In this case, Ricardo points out, wages are forced down by competition among workers, and the introduction of new machines can lead to an overall decline in the well-being of the working class.