Thomas Robert Malthus was an influential British economist best known for his theory on population growth, outlined in his 1798 book "An Essay on the Principle of Population."

In it, Malthus argued that populations inevitably expand until they outgrow their available food supply, causing the population growth to be reversed by disease, famine, war, or calamity.

He is also known for developing an exponential formula used to forecast population growth, which is currently known as the Malthusian growth model.