Mathematical Preliminaries -- Vector Calculus -- Partial Differential Equations -- Theory of Generalized Convexity -- Calculus of Variations and the Optimal Control -- Miscellaneous Techniques -- Economics of Multidimensional Screening -- The Unidimensional Screening Model -- The Multidimensional Screening Model -- Beyond the Quasilinear Case -- Existence, Uniqueness, and Continuity of the Solu…