Donald Walker and Jan van Daal's recently translated the 3 rd edition of Léon Walras's Éléments d'économie politique pure under the title Elements of Theoretical Economics, in place of the conventional translation Elements of Pure Economics. This critical note points out that this new English title for Walras's Éléments is inappropriate because it ignores Walras's position as founder of the 'Lausanne school', with Vilfredo Pareto, as Walras's successor, embracing Walras's term 'pure' economics and, in his Cours d'économie politique, creating a distinction between pure and applied economics that is inconsistent with the translation of économie politique pure as 'theoretical economics'.