This article examines radical and socialist responses to Malthus's Essay on population, beginning with the response of William Godwin, Malthus's main object of attack, but focusing particularly upon the position adopted by his most important admirer, Robert Owen. The anti-Malthus position was promoted and sustained both by Owen and the subsequent Owenite movement. Owenites stressed both the extent of uncultivated land and the capacity of science to raise the productivity of the soil. The Owenite case, preached weekly in Owenite Halls of Science, and argued by its leading lecturer, John Watts, made a strong impact upon the young Frederick Engels working in Manchester in 1843–4. His denunciation of political economy in the Deutsch-Französische Jahrbücher, heavily dependent upon the Owenite position, was what first encouraged Marx to engage with political economy. Marx initially reiterated the position of Engels and the Owenites in maintaining that population increase pressured means of employment rather than means of subsistence, and that competition rather than overpopulation caused economic crises. But in his later work, his main criticism of the Malthusian theory was its false conflation of history and nature.