This series consists of about sixty letters that Buyse wrote between 1917-1944. Most of these letters are addressed to a friend, Rose Alden, and the series contains many copies and extracts of Buyse's letters that Alden prepared. In her letters, Buyse describes her life and work in Africa, where she served as a missionary for the Africa Inland Mission, an international organization founded in 1895. She discusses teaching women and children at mission boarding schools and the problems associated with that work, such as the difficulty of learning many local dialects. Buyse also mentions her many other tasks, which included serving as a midwife. She traveled widely in Africa and describes her many visits to missionary stations, schools, and conferences, as well as occasional vacations. She also discusses social and political conditions in Africa, including outbreaks of disease and famine; customs related to housing, clothing, food, and celebrations; government policies and responses to local uprisings; and the impact of world events such as World Wars I and II and the worldwide economic depression of the 1930s on Africa. In addition, Buyse mentions many details of her personal life. She discusses her religious faith and missionary philosophy; her marriage and work with her husband; her health, loneliness and feelings of discouragement with the progress of Protestant mission work in Africa; and the pleasure that she receives from writing music to hymns and reading books by Dicken, Proust, and others.

This series includes Buyse's published writings about her missionary experiences teaching English and religion in various African villages between circa 1919 and 1945. These writings are descriptive sketches of the lives and culture of the African villagers whom Buyse interacted with as a missionary. Several documents are articles from the missionary magazine, "Inland Africa." These articles give Buyse's impressions of people of Arua, a village in the Belgian Congo circa 1919-1928, Lugbara Village, Belgian Congo, before 1939, and Tanganyika, Kenya in 1944. A small book of narratives entitled "Missionary Cameos" briefly describes various "branches of the work of the Africa Inland Mission in Congo." This booklet includes photographs and narrative sketches of the Nadi tribe, Mwanza Bay, the Aba and Adi Villages of the Belgian Congo, and Goli, Uganda. Of particular interest is Buyse's book, "Nyilak and other African Sketches," published in 1923. The manuscript copy of the first chapter of "Nyilak" is included in Buyse's writings.

This series consists of cards, brochures, and maps from Buyse's missionary travels between circa 1928-1955. Included in the documents are a business card of Rev. and Mrs. John G. Buyse and two cards advertising the Africa Inland Mission, one with photographs of Buyse and her husband and their travel route from New York to Aba, Belgian Congo. Also contained in this series are two maps of the "Fields and Stations of the Africa Inland Mission" drawn by John Buyse in 1937 and 1938.

This series contains articles, notes, Mount Holyoke Class of 1907 reports, and Buyse's memorial service program. Of particular interest in this series is a statement by R. Floyd Pierson, a friend and fellow African missionary, entitled "In Memorium of Mabel Easton Buyse" and written after her death in 1977. In this document, Pierson gives his recollections of Buyse and records many of her beliefs about religious faith.

This series consists of formal and informal photographs of Buyse and her husband taken between 1913 and 1958. The photograph from 1913 is captioned "Leaving Jersey" and shows Buyse in travel clothes at a ferryboat dock. There are four formal photographs and three snapshots of Buyse and her husband by their home and church in Florida in about 1958.