This chapter considers the influence of Malthus on Darwin; and how Darwin adapted for application to the non-human living world part of a theoretical scheme originally modelled on Newtonian classical mechanics, and only later and not thoroughly altered to make room for the realities of choice. It shows whether there was any direct or indirect contribution from Adam Smith and the other Scottish founding fathers of social science. The chapter ignores the unrewarding question of possible Darwinian influence on Marx, investigating instead two other issues: whether Darwin's theory does in truth supply any sort of support for the revolutionary revelations of The Communist Manifesto; and whether we can accept the claim that Marx was, in his different field, a scientist of the same stature as Darwin. It ends with the claims and ambitions of sociobiology, that Neo-Darwinian candidate discipline whose practitioners aspire to re-establish authentically scientific social sciences upon properly biological foundations.