I am a graduate of the Universities of Oxford and Aberdeen, beginning service in West Africa in 1957, working at Fourah Bay College, Sierra Leone, and at the University of Nigeria, Nsukka, where I was Head of the Department of Religion. For many years I was Professor of Religious Studies and Riddoch Lecturer in Comparative Religion at the University of Aberdeen, before becoming founding Director of the Centre for the Study of Christianity in the Non-Western World at the University of Edinburgh. I have lectured in all six continents, and been Visiting Professor of World Christianity at Yale and at Harvard Universities.
I am an Officer of the Order of the British Empire, a past President of the British Association for the Study of Religions, a past General Secretary of the International Association of Mission Studies, and a Fellow of the Society of Antiquaries of Scotland. I have published widely in the fields of Christian History, World Christianity and was founding editor of the Journal of Religion in Africa. My best-known publications include The Missionary Movement in Christian History (Orbis 1996) and The Cross-Cultural Process in Christian History (Orbis 2002). I am also General Editor of the Methodist Missionary History Project.