An argument that complex cardinals are not extra-linguistic but built using standard syntax and standard principles of semantic composition.In Cardinals, Tania Ionin and Ora Matushansky offer a semantic and syntactic analysis of nominal expressions containing complex cardinals (for example, two hundred and thirty-five books). They show that complex cardinals are not an extra-linguistic phenomenon (as is often assumed) but built using standard syntax and standard principles of semantic composition. Complex cardinals can tell us as much about syntactic structure and semantic composition as other linguistic expressions.Ionin and Matushansky show that their analysis accounts for the internal composition of cardinal-containing constructions cross-linguistically, providing examples from more than fifteen languages. They demonstrate that their proposal is compatible with a variety of related phenomena, including modified numerals, measure nouns, and fractions. Ionin and Matushansky show that a semantic or syntactic account that captures the behavior of a simplex cardinal (such as five) does not automatically transfer to a complex cardinal (such as five thousand and forty-six) and propose a compositional analysis of complex cardinals. They consider the lexical categories of simplex cardinals and their role in the construction of complex cardinals; examine in detail the numeral systems of selected languages, including Slavic and Semitic languages; discuss linguistic constructions that contain cardinals; address extra-linguistic conventions on the construction of complex cardinals; and, drawing on data from Modern Hebrew, Basque, Russian, and Dutch, show that modified numerals and partitives are compatible with their analysis.