Roman Jakobson and Claude Lévi-Strauss met in New York in 1942 and soon started a collaboration and a written correspondence that went on as long as 1982. Both the National Library of France and the Institute Archives and Special Collections of the Massachusetts Institute of Technology keep the correponding letters, about 160 of which were published in 2018. This paper aims at publishing thirty-four new letters that are presented in their respective contexts. These unpublished exchanges bring new insights into Jakobson and Lévi-Strauss' works and collaboration.