This chapter is in search of the evolutionary leap from animal existence to human being. First, the Marxist legacy is visited; the roots of Marxism in German Romanticist philosophy, British Political Economy, and French radical politics are recapitulated. Next the Classical Anthropogenesis from Democritus to Jean-Jacques Rousseau is described with its defining Robinson features. Then it is shown how Friedrich Engels' essay, "The Part Played by Labour in the Transition from Ape to Man," is just an upgraded version of this classical story. Finally, it is concluded that nowhere in this historical corpus of Enlightenment thought is a leap into difference in kind identified.