 Montague used \(\lambda\)-abstraction, which at the time was not a standard ingredient of logic. As illustrated in section 4.1, the \(\lambda\)-operator makes it possible to express higher-order functions, which may serve as the contributions that parts of sentences make to their truth-values. The importance of \(\lambda\)-expressions was once expressed by Barbara Partee in a talk on ‘The first decade of Montague Grammar’: ‘Lambdas changed my life’ (Partee 1996, 24). Nowadays \(\lambda\)-expressions are a standard tool in natural language semantics, and particularly in the type-driven approach made popular by Heim and Kratzer (1998). In section 4.1, an example will be given that illustrates the power of \(\lambda\)-expressions.