The study of Soviet-American scientific relationships during the Cold War is an actual scientific task. In the article for the first time is published letters from the personal foundation of Professor Michael Sjuzjumov (Ural University, Sverdlovsk), which he received from Lois Hassler-Smith and Merlin Packard, librarians of the Center for Byzantine Studies at Harvard University in Dumbarton Oaks, 1960s and 1970s. In addition, the author of the article is considered the issue of official ways to exchange scientific literature with capitalist countries, which were regulated by special legislative acts. However, the contacts that scientists of the USSR and the United States independently established among themselves made it possible, avoiding unnecessary formalities, to quickly receive the latest scientific literature. The letters published in the article indicate that the correspondence of M.Ja. Sjuzjumov with the staff of the Dumbarton Oaks library lasted more than 10 years. The American side received scientific periodicals published in Sverdlovsk and teaching aids on special courses, and M.Ja. Sjuzjumov – novelties of American scientific literature and classical editions, which were previously available to him only in the capital’s libraries. The authors of the article also managed to identify an error made by the compilers of the Who Was Who at Dumbarton Oaks index, 1940–2015. This edition indicates that the library employed female employees Lois Smith and Lois Hassler. Meanwhile, the analysis of correspondence with M.Ja. Sjuzjumov and the data of the American periodical press prove presented one person – Lois Hassler-Smith.