This collection consists of the dissertation of K. James Stein at Union Theological Seminary, submitted in 1965. There is a single volume of roughly 320 typed pages. Its focus is on the various Ecumenical currents within the Church of the United Brethren in Christ and its forerunners, along with its occasional attempts at union with denominations such as the Methodist Episcopal Church. Stein examines the attempts and explains their origins, progress and ultimate reasons (in attempts at union) for failure. The time-span largely focuses on the 19th century, with some early focus on the late-18th century. Stein depicts the ethos, and rural emphasis of the Brethren sects along with their involvement in foreign missionary work. He also makes a significant focus of the pietistic elements in Church of the United Brethren doctrine, attitude, and worship.

This collection is made up of records of the various agencies of the church. It also includes material regarding local churches and annual conferences. The collection is made up of thirteen series. The three largest series which make up the bulk of the collection are the Missionary Society, the Woman's Missionary Society, and the Board of Christian Education.

This collection is made up of the administrative material from the Board of Missions. It also includes the records of the World Mission Division, the Division of Home Missions and Church Extension and its various departments and mission fields, the National Missions Division and the Mission Advance Program. The collection is made up of six series. Although there is some material from 1862 and the 1970's, the bulk of the material is from 1946 to 1968.