Saint Antoninus of Florence was a Dominican friar and archbishop of Florence from 1446 to 1459. He composed one of the most comprehensive manuals of moral theology, the Summa, which has long been counted among the more copious, influential, and rewarding medieval sources. St Antoninus of Florence on Trade, Merchants, and Workers gives an orientation to the life and teaching of Saint Antoninus, focusing on his writings on economic ethics, and includes a critical edition of his original Latin text with an English translation. The book provides an extensive introduction to his thought, situating it in its intellectual and social context, and elucidates the development of medieval economic and moral doctrines in law and theology. Jason Aaron Brown examines historians’ arguments about Italian business culture in the wake of the medieval “Commercial Revolution” and whether this culture can be considered capitalistic. He concludes that while Saint Antoninus is surprisingly modern in the economic concepts he deploys, his moral teaching on proper means and ends in the marketplace stood against certain nascent capitalistic tendencies in fifteenth-century Florence. Through examination of the manuscripts, this book opens a window into a premodern author’s writing process that will be of interest to scholars of medieval manuscripts and literary production.