This chapter introduces Linguistics in Schools (LiS) as an educational movement and research field, and discusses the place of ‘theoretical linguistics’ (or TLiS) within it. The chapter serves to situate the TLiS project as it is understood in the present book in terms of i) its relationship to the discipline of linguistics (and beyond); and ii) its rationale, as expressed by advocates of incorporating theoretical linguistics into pre-university education. It also considers some wider aspects of implementing TLiS in practice. Insights from the volume’s component chapters are interwoven throughout these discussions. The chapter ends with an outline of the thematic and structural organization of the volume, and offers synopses of the collection’s individual contributions.