This essay is intended as a scholarly contribution to the construction of a detailed biography of Lacan’s 1966 Écrits, which is conceived here as a living entity whose influence continues to radiate around the world, within as well as outside psychoanalytic circles. Documenting and re-evaluating the historical circumstances presiding over the book’s gestation, birth and coming of age, the essay first argues that, despite the multiplicity inscribed in its title, Lacan’s volume constitutes an integrated unity rather than a mere collection of disparate papers written over a period of thirty-odd years, albeit a unity that is fundamentally incomplete. Subsequent to this, it is proposed that Lacan’s choice of title (Écrits, writings) occasioned the crystallisation of his own theory of the letter, writing and (knowledge) transmission. Even though this theory was already contained in statu nascendi in two of the papers collected in Écrits, it was only through a process of deferred action that Lacan came to appreciate its significance. Aligning writing with the object a, as cause of desire, Lacan’s theory both underpinned his opposition to Jacques Derrida’s deconstruction of logocentrism (and his concurrent promotion of writing as a primordial trace), and informed his own protracted consideration of the transmission of psychoanalytic knowledge during the 1970s via a series of (mathematical and topological) writings.