This paper develops an assignment model of automation. Each of a continuum of tasks of variable complexity is assigned to either capital or one of a continuum of labor skills. The researchers characterize conditions for interior automation, whereby tasks of intermediate complexity are performed by capital. Interior automation arises when low-skill wages are low and effective cost of capital in low-complexity tasks is high. Minimum wages make interior automation less likely. Higher capital productivity causes employment and wage polarization, changes the skill premium non-monotonically, and reduces the real wage of workers with comparative advantage profiles close to that of capital.