Reviewer Perry Smith for MathSciNetwrote: "The author's ideas on how to achieve both intelligibility and rigor, explained in the preface, will be useful reading for anyone intending to teach nonstandard analysis."
Goldblatt, Robert. Topoi: The Categorial Analysis of Logic. Dover Books on Mathematics, 1984.
Benjamin C. Pierce recommends it as an "excellent beginner book", praising it for the use of simple set-theoretic examples and motivating intuitions, but noted that it "is sometimes criticized by category theorists for being misleading on some aspects of the subject, and for presenting long and difficult proofs where simple ones are available."
Goldblatt, Robert. Mathematical Modal Logic: a View of its Evolution. in Modalities in the Twentieth Century, Volume 7 of the Handbook of the History of Logic, edited by Dov M. Gabbay and John Woods, Elsevier, 2006, pp. 1–98.