This thesis is a conceptual-historical analysis of the political thought of Thomas Robert Malthus. In particular, I will highlight how the late Eighteenth-century revolutionary crisis, combined with the economic and social upheavals connected to the birth of the first factory-systems, led the author to rethink some fundamental concepts of modern political thought. Population, society, government and constitution are the main objects of my research: the principle of population is the scientific law that Malthus formulated to elaborate his theories on government, which for him must always aim at preserving – or improving – the constitution of society. The political presence of masses of poor people in society pushed the author to find a scientific principle capable of grounding in nature the hierarchies that were contested by many; insofar as they depend on “fundamental laws”, for Malthus hierarchies and inequality are constitutive of society. Theology, morality and political economy are the main disciplines that the author used both to argue that poverty and female “delicacy” are natural, and to affirm the ways in which they can be profitably governed. In India and Ireland – two places that Malthus looked at because of the strategic position they occupied within the British Empire – the natural conditions of which the principle of population seals the necessity are found to be subject to completely original challenges compared to those observed in England. There, the Malthusian effort to construct a science equal to the social object reveals its ambition to naturalise politics and guarantee the conditions for disciplining individuals, men and women, to work and stop nourishing “unreasonable” expectations of wellbeing. The naturalisation device that lies at the heart of the Malthusian system represents a key element of the Malthusian problem that opens this research and marks its salient moments.