This chapter describes precursors to CDA, and important foundational concepts and theories. We first review briefly the ideas of the British linguist, John Rupert Firth, and his anthropologist colleague, Bronislaw Malinowski, and then discuss Michael Halliday’s Systemic Functional Linguistics (SFL), Systemic Functional Grammar (SFG) and Language as Social Semiotic (SocSem) and some ideas originated by James Martin—including his stratal-functional model, notions of text and context (and register and genre), the three metafunctions, grammatical metaphor and ‘appliable linguistics’. Next, we describe critical linguistics (CritLing): its relation to other approaches, its definition, important works such as Language and Control and Language as Ideology, its interdisciplinarity and ‘useability’ as an approach, and its further development in Kress (1985b/1989), Linguistic Processes in Sociocultural Practice. We then discuss the complex relationship between CritLing and SocSem, the further development of SocSem in Hodge and Kress (1988) and especially in Kress and Theo van Leeuwen’s work on the ‘grammar’ of visual design in Reading Images (1996), including the three metafunctions and other facets of the visual. We conclude with the development of multimodality—and a short discussion of Kress and van Leeuwen’s Multimodal Discourse in relation to CritLing, SocSem, and CDA.