The extraordinary development of scientific technology, of the productivity of labor, and to some extent of the customary levels of working-class consumption during this century have had, as has often been noted, a profound effect upon the labor movement as a whole. The unionized working class, intimidated by the scale and complexity of capitalist production, and weakened in its original revolutionary impetus by the gains afforded by the rapid increase of productivity, increasingly lost the will and ambition to wrest control of production from capitalist hands and turned ever more to bargaining over labor’s share in the product. This labor movement formed the immediate environment of Marxism; and Marxists were, in varying degrees, compelled to adapt themselves to it.