Thomas Malthus is read primarily for An Essay on the Principle of Population, a foundational work of political economy and demographic thought. The essay argues that population has a tendency to grow faster than the food supply and therefore encounters checks such as delayed marriage, poverty, disease and famine. Later editions greatly expanded the original argument with historical and statistical material, turning a short intervention in debates about social perfectibility into a broader study of population and subsistence. Malthus's prose is formal, argumentative and rooted in late-eighteenth- and early-nineteenth-century political economy rather than modern population science. His work fits economics, demography, history of ideas and classical political thought. An Essay on the Principle of Population is the essential starting point, but readers should note that Malthus revised it substantially, so abridged editions and the first 1798 text can differ markedly in tone, evidence and scope. Read more Less