Part I. Foundations -- The econometric approach -- The measurability of utility -- The preference hypothesis -- The logic of order -- Strong and weak ordering in demand theory -- Part II. The demand for a single commodity -- The direct consistency test -- The demand curve -- Indifference and the compensating variation -- Marginal valuation -- Consumer's surplus -- Part III. The general theory of demand -- Consistency tests -- The substitution effect -- The reciprocity theorem -- Secondary substitution theorems -- The income effect -- Substitutes and complements in valuation theory -- Complements and substitutes further considered -- Generalized consumer's surplus -- The index-number theorem -- Summary and conclusion.