'Mood' (subjunctive, etc.) and 'modality' (can, may, must, etc.) are familiar terms in linguistics, but this is the first book to present a systematic and principled description, across a wide variety of languages, of what can be considered a single grammatical category. The notion of modality is notoriously vague and a number of definitions have been proposed, encompassing the attitude or opinion of the speaker, speech acts, subjectivity, non-factivity, non-assertion, possibility and necessity. Often such definitions have been language-specific. By examining data (including data on evidentials) from many different languages - native American and Australian languages, for example, as well as Latin, Greek, English and others - F. R. Palmer is able to compare and contrast the ways in which modality is grammaticalized, its various functions, and its relation to other grammatical categories. From this typological approach arise cross-linguistic generalisations and theoretical conclusions that will interest the specialist as much as the advanced student. Written with F. R.