This new edition is an introduction to systemic functional linguistics which explores the social semiotic approach to language most closely associated with the work of M.A.K. Halliday. It incorporates several important developments within systemic linguistics, including a new chapter on the logical relations of the clause complex, discussion of the application of systemic linguistics to the analysis of multi-modal texts and clarification of systemics as a critical theory of meaning in the context of post-structuralist critical and cultural theories.