Editions of the Kitāb
I recently came across Jean Druel's amazing Three Western Recensions of Sībawayh’s Kitāb[1]. It presents “an edition [of the Kitāb] encompassing the three recensions contained in the Milan-Kazan codex, arranged in three parallel columns.” I don't know when I'll find the time to read the recensions, but the Introduction alone is hugely valuable. Building on the the seminal work of Humbert[2], it contains a detailed discussion of various manuscripts and editions of the Kitāb. Discussing the editions in print today, Druel concludes:
[O]nly [two] editions enable scholars to link between the recensions and the manuscripts, namely that of Derenbourg (on which Būlāq and Hārūn are based) and al-Bakkāʾ.
So I'm using the al-Bakkā edition as the basis of my editing. It's not perfect; in fact it contains quite a few typos. But it does take previous editions as well as (some) manuscripts into account, so that's what I'm going with.
[1] Druel, Jean N. and Sībawayhi (2025). Three Western Recensions of Sībawayh’s Kitāb: A Critical Edition of Ambrosiana X 56 Sup. & Kazan National Archives 10/5/822. Ed. by Jean N. Druel. Leiden, The Netherlands: Brill. ISBN: 978-90-04-72943-8. DOI: 10.1163/9789004729438. URL: https://brill.com/view/title/72143
[2] Humbert, Geneviève (1995). Les voies de la transmission du Kitāb de Sībawayhi. Leiden ;;New York: E.J. Brill