This series covers the years from 1944 to 1994 and is arranged alphabetically. Representative correspondents include Mexican, American, British, French and Spanish publishers, literary agents, faculty and administrators at colleges and universities throughout the U.S., Mexico, Latin America, and Europe, and writers, translators, theater directors, and filmmakers. Correspondence with publishers Farrar, Straus & Giroux covers 1963-1993; Éditions Gallimard, 1961-1993; Fondo de Cultura Económica, 1961-1993; Editorial Joaquín Mortiz, 1965-1984; and Editorial Seix Barral, 1967-1985. There is also a large amount of correspondence with members of Fuentes' family, especially his mother, Bertha Macías de Fuentes, and father Rafael Fuentes Boettiger, and some correspondence of Carlos Fuentes with friends in the 1950s. Some of the folder titles follow Fuentes' own labels used in filing correspondence. There are many letters from readers and students, filed chronologically, in the folders labeled "Students and Readers."

The author's correspondence with government officials of Mexico and France, in particular, is filed in either of two places—and in a few instances in both—under the corporate body, e.g., Mexico. Secretaría de Relaciones Exteriores, or under the person, e.g., Flores Olea, Ambassador Victor. This rule of filing applies also to some literary figures, e.g., editor Ugné Karvelis, whose correspondence is located under Éditions Gallimard, and also under her name. In the finding aid, folders which have corporate body titles are often given an additional description of the main individual correspondent, or correspondents, in parentheses, e.g., Editorial Diana (José Luis Ramírez). If there is more than one folder for the correspondence of a corporate body, the range of dates for each folder is also included.