Add to ORKGFriedrich Engels along with Karl Marx are the builders of the materialist conception of history, the critique of political economy and scientific socialism. And upon reflecting on the communist project for the emancipation of humanity, they conclude that overcoming material scarcity is the fundamental economic condition for carrying out the total realization of said project. In particular, when Engels correlates and identifies respectively the concepts of the kingdom of necessity and the kingdom of freedom with Marx's concepts of the prehistory of humanity and truly human society; not only does it philosophically substantiate them, but it also gives them historical and material specification. Herein lies Engel's contribution to the project ...