With its 349 issues, the recently published correspondence between Roberto Longhi and Federico Zeri (1946-1965) is the most extensive of Longhi's correspondence published to date. The article examines the forms and ways in which epistolary material of the recent past can be made known, particularly relating to art history. A profile of the relationship between the two scholars, of different generations and of different scientific and moral standing, also emerges from this reflection.