This paper offers a unified analytical treatment of Marx’s theory of rent. I highlight the key role played by the price of the agricultural commodity in determining rent. I offer two closures of the model. The first closure is an elaboration of Marx’s argument in Volume III of Capital. The second closure explicitly allows for the role of demand. I also show that total rent can be decomposed into three components: absolute rent, differential rent I, and differential rent II. A Marxist theory can explain rent in any system of capitalist commodity production which uses privately owned nonreproducible resources.