This essay elaborates on Roberto Longhi's reading of Giorgio Vasari's Lives, spanning a period of about fourty years, from Longhi's debut on 'La Voce' (1911) to his decisive Proposte per una critica d'arte (1950). Firstly, it discusses the importance of Vasari's influence in shaping Longhi's aptitude to read artworks as well as to use artistic literature in the early years of his training as an art historian. Secondly, it offers an examination of Longhi's main studies on Piero della Francesca (1914; 1927), showing how the scholar adopts the data and vocabulary of the Lives against the positivist tradition. Thirdly, it delves into the 'Fatti di Masolino e di Masaccio' (1940), casting light on Longhi's ability to distinguish between the texts of both editions of the Lives, namely the Torrentiniana (1550) and the Giuntina (1568). Finally, it shows how Longhi's familiarity with Vasari's work gives rise to a different, multifaceted geography of Italian art, as the Stefano Fiorentino (1951), in particular, suggests. By addressing some stylistic, historiographical and aesthetic issues, the paper aims to clarify Longhi's position in the context of the critical debate on Vasari during the 19th and 20th centuries (from Cavalcaselle to Berenson and Lionello Venturi).