There are fewer letters after The Rake's Progress reunion, the result of Stravinsky and Boulanger's immensely busy schedules in the 1950s. In this decade, both musicians rose to new levels of professional prestige. Though Boulanger turned down the majority of North American invitations she received, she otherwise commonly references tours returned from or those for which preparations were under way. For both musicians, brevity and concision became essential, which may explain some of the changes in rhetoric that creep in, including Stravinsky sometimes writing to Boulanger in English or sending dictated letters entirely missing diacritical marks.

In 1953, Boulanger was appointed Director of the Écoles d’art américaines at Fontainebleau, and she threw herself into the role with vigor. She believed fervently, as she wrote to Stravinsky on September 21, 1953, that she wanted “the École de Fontainebleau to have a real purpose, or else [they] should let it go.” This new directorship drove her. For Stravinsky, the years directly following 1951 were ones of significant metamorphosis. His experience touring Europe after the premiere of The Rake's Progress exposed him to a musical world vastly different from that of the United States. He deeply feared he had fallen by the wayside and would be omitted from the music-historical narrative. I suspect Boulanger, too, remained sensitive to Stravinsky's insecurities, given the frequency with which she reassured the composer that he continued to hold sway on the continent.

One of the greatest factors affecting the rapport between Boulanger and Stravinsky rested in the latter's decision to explore serial composition. In 1952, Stravinsky began to experiment with these precompositional procedures, a decision no doubt made easier following the death of Arnold Schoenberg on July 13, 1951. Stravinsky was also encouraged in this pursuit by his new assistant, Robert Craft (1923–2015), a young conductor who had studied at Juilliard and was a passionate champion of modern music. This is the “Bob” mentioned by Boulanger in letters beginning on September 20, 1952. Craft's own dialogue with Stravinsky began soon after the war, and by December 1948 Craft had moved into the Stravinskys’ home to serve as the composer's amanuensis and assist with his professional endeavors.