This document provides an overview of different theories of wages. It discusses subsistence theory, which states that wages will tend toward the minimum needed to keep workers alive. Wages fund theory argues wages are paid from a predetermined fund. Surplus value theory says workers are paid less than the value they create, with the surplus going to expenses. Residual claimant theory views labor as the residual claimant to the value created after other factors are paid. Marginal productivity theory holds that wages are determined by how much value workers add at the margin.