Syncretism--where a single form serves two or more morphosyntactic functions--is a persistent problem at the syntax-morphology interface. It results from a 'mismatch' whereby the syntax of a language makes a particular distinction, but the morphology does not. This pioneering book provides the first full-length study of inflectional syncretism, presenting a typology of its occurrence across a wide range of languages. It will be welcomed by all linguists interested in the relation between words and the larger units of which they are a part.