Mirrlees\' 1971 paper (An Exploration in the Theory of Optimum Income Taxation) on optimal taxation can sometimes be hard to follow. Does anybody know of (or could even provide here) a simple sketch of the derivations of the optimal nonlinear income tax schedule in his paper? Solution You can find a didactic exposition of Mirrlees (1971) including derivations of optimal tax schedule formulas for different social welfare and utility function in section 4.2 of \"The Economics of Taxation\" by Bernard Salani.