For nearly half a century, Professor M. A. K. Halliday has been enriching the discipline of linguistics with his keen insights into the social semiotic phenomenon we call language. This ten-volume series presents the seminal works of Professor Halliday. This third volume includes papers that explore different aspects of language from a systemic functional perspective. The papers are organized into three sections: the place of linguistics as a discipline; linguistics and language; and language as social semiotic. In addition, there is a new work from Professor Halliday, entitled 'On the architecture of human language', in which he focuses on the assumptions or working hypotheses that enabled him to explore important questions about this massive semiotic power called 'language'.