Assertion - the act of presenting what we say as true - is at the centre of human social life. Yet what might seem a relatively simple phenomenon has proved difficult to define or characterise successfully. Is assertion just another speech act, on a par with promising, ordering and the like, or is it more fundamental? How is assertion related to belief? Does the declarative mood have a special role to play in the correct analysis of assertion or can assertion be characterised independently of linguistic form? What is the relationship between what a speaker asserts and her main point? All these questions are addressed in this book as the author develops a novel account of the pragmatic processes involved in assertion and the role of the declarative mood in those processes. In doing so, he synthesises a range of perspectives on assertion, drawing on the work of philosophers, linguists and cognitive scientists.