Acknowledged as influential within the context of late medieval architecture in Italy, the Dominican church of Santa Maria Novella in Florence has not attracted the substantive architectural study it deserves. The book re-envisions its building history, focusing on crucial stages in its creation: the original model commissioned in the 1270s, and the radical 14th-c. redesign of the nave. Analysis of previously unobserved features illuminates the creative process, enabling a firmer attribution of authorship and a new chronology for its groundbreaking vaulted nave.