Fundamentally, the history of the world's societies has been a history of the struggle for wealth and private property, and labor is the force of that struggle. Even Karl Marx, in whose name social historians frequently write, knew that it was not the working class but the middle classes that drove history along its progressive path. Capitalism requires a free state in which people can make choices in what they buy and produce. Marxism looks at capitalism as slavery. The history of all hitherto existing society is the history of class struggles. 6 pgs. Bibliography lists 6 sources.