The paper uses basic theories of Marx on social structure and Malthus on demography to explain many features of Arabia in terms of the arid environment. The focus is on traditional Arabia, but it is argued that the same consideration continue to apply to modern Arabia. Beginning with the desert, it is argued that the only viable economic activity in ‘traditional’ Arabia was herding, and the only feasible system of property was communal ownership. Malthusian demography implies that the