This book was inspired by the late Professor Francesco del Punta, at whose invitation I gave a series of lectures on Kilwardbyâs logic at the Scuola Normale Superiore, Pisa, in 2009.
I thank Alessandro D. Conti for making available to me his transcriptions of Kilwardbyâs commentaries on Porphyry and on the Categories and the Peri Hermeneias.
Over the years, numerous friends and colleagues have variously encouraged, supported, and criticised my attempts to capture Kilwardbyâs thought; most of them have done all these things. They include Allan Bäck, Julie Brumberg-Chaumont, Catarina Dutilh Novaes, Sten Ebbesen, Heine Hansen, Ahmad Hasnaoui, Simo Knuuttila, Henrik Lagerlund, Chris Martin, Joshua Mendelsohn, Stephen Menne, Calvin Normore, Stephen Read, Irène Rosier-Catach, Tony Street, Riccardo Strobino, Christina Thomsen-Thörnqvist, and especially John Marenbon.
I thank an anonymous reviewer for reading the manuscript with great care and for making numerous helpful critical suggestions and corrections.