The Reverend Thomas Robert Malthus FRS (1766-1834), was a British scholar, influential in political economy and demography. He popularised the economic theory of rent. Between 1798 and 1826 Malthus published six editions of his famous treatise, An Essay on the Principle of Population, updating each edition to incorporate new material, to address criticism, and to convey changes in his own perspectives on the subject. Malthus regarded ideals of future improvement in the lot of humanity with scepticism, considering that throughout history a segment of every human population seemed relegated to poverty. He explained this phenomenon by pointing out that population growth generally preceded expansion of the population's resources, in particular the primary resource of food. Malthus, sometimes regarded as "the founding father of modern demography", continues to inspire and influence futuristic visions. He became hugely influential, and controversial, in economic, political, social and scientific thought. Many of those whom subsequent centuries sometimes term "evolutionary biologists" also read him, notably Charles Darwin and Alfred Russel Wallace, for each of whom Malthusianism became an intellectual stepping-stone to the idea of natural selection.