Class is the objective and concrete division of society based on the division of labor. The fundamental division of labor was based on sexual difference (men and women had different jobs owing to a difference in relation to the reproduction of the tribe/humanity).[1]
Every society in history so far has been a form of class society:[2] in slavery, the master and slave; in feudalism, the lord and serf; in capitalism, the bourgeoisie and proletariat.
The stage in which class society rots and decays once and for all is capitalism; the stage which takes it's place and paves the road out of class society is (the mode of production of) socialism. The real movement of the people, the seizure of the private property and the bourgeois state by the proletarian class, is Communism.