We live our lives in conversation, building families, societies and civilisations. In over seven thousand languages across the world, the basic infrastructure by which we communicate remains the same. This is the first ever book-length linguistic introduction to conversation analysis (CA), the field that has done more than any other to illuminate the mechanics of interaction. Starting by locating CA by reference to a number of cognate disciplines investigating language in use, it provides an overview of the origins and methodology of CA. By using conversational data from a range of languages, it examines the basic apparatus of sequence organisation: turn-taking, preference, identity construction and repair. As the basis for these investigations, the book uses the twin analytic resources of action and sequence to throw new light on the origins and nature of language use.