Rent theories examine the determination of land rent and the gains and losses to different classes from its payment. Different analyses of rent suggest different strategies for the working class. This paper discusses rival rent theories developed in the nineteenth century. After outlining the theories of Marx and Engels, Proudhon and George, the paper turns to the strategic situations in which they were formulated, showing their dependence on particular housing problems of the time. Both the positions of Engels and of George are shown to be valid in some respects, but incomplete in others. Merged with a Georgite attack on land monopolies, Engels' concern with working class unification could have suggested a more effective strategy. In a final section, the theories are applied to recent urban and housing crises. The theories of Proudhon and Marx are used to iden tify possible barriers to housing construction, and proposed stategies are shown to assume different barriers are most important.