'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. Palmer's characteristic clarity and attention to detail, Mood and modality is a major contribution to our understanding of a basic topic in language studies.