Leading Methodist historian, he was born in Hull on 15 April 1910. He was converted during the Humberside Crusade of 1924. Accepted for the PM ministry, during his years at Hartley College he obtained his London BA and Manchester BD. A Nottingham PhD for a thesis on William Grimshaw followed in 1952. He served in English circuits until 1959; then, after two years lecturing in religious studies at Hull Training College, in 1960 joined the staff of Duke University, Durham NC, where he nurtured a whole generation of Wesley scholars. He was four times the winner of the Eayrs Essay Prize between 1936 and 1948; was Registrar of the Wesley Historical Society 1943-1949 and its Secretary 1946-61; and was Secretary of the British Methodist Archives Commission 1955-60. He served on the World Methodist Council 1944-1960 and as joint secretary of the International (now *World) Methodist Historical Society 1947-1960. He was made a Fellow of Methodist History in 1956.
He was the chief initiator and Editor-in-Chief of the Wesley Works Project, edited the first two volumes of John Wesley's letters and the (as yet unpublished) Bibliography of Wesley's publications. A prolific writer, his books include Charles Wesley as Revealed by his Letters (WHS Lecture, 1948), William Grimshaw (1963), John Wesley and the Church of England (1970) and From Wesley to Asbury (1976). He also wrote, for the general reader, A Charge to Keep (a useful introduction to Methodism, 1947) and A Methodist Pilgrim in England (1951). He has been honoured internationally for his outstanding and sustained contribution to Methodist historical studies. In 1994 he was awarded the St. George's Gold Medal for distinguished service to the United Methodist Church. He died in Durham NC on 11 October 1999.