Alan Philip Frederick Sell (b. Nov. 15, 1935) was formerly Professor of Christian Doctrine and Philosophy of Religion at the United Theological College, Aberystwyth (Wales). He has written in the areas of philosophy, theology, ethics, and history and has held leadership roles in mainline ecumenical organizations such as the World Alliance of Reformed Churches. His book The Great Debate: Calvinism, Arminianism and Salvation (Baker, 1983) introduced the phrases "Armianism of the head" and "Armianism of the heart", which were made more well known through Roger E. Olson's Arminian Theology: Myths and Realities (IVP, 2006).
He has a PhD (1967) and is a Fellow of the Royal Historical Society, the Royal Society of Antiquaries, and received a Doctorate of Divinity from the University of Manchester, based on his many published works. He holds Honorary Doctorates in Divinity from Ursinus College (Pennsylvania) and Acadia University (Nova Scotia), and an Honorary Doctorate of Theology from the University of Debrecen (Hungary).
- The Great Debate: Calvinism, Arminianism and Salvation. Baker Book House, 1983. ISBN 0801082277.
- Defending and Declaring the Faith: Some Scottish Examples, 1860-1920. Contributor James B. Torrance. Helmers & Howard, 1987. ISBN 0939443023.
- God Our Father. White Mane Pub, 2000 (Revised. 1st Edition, 1980). ISBN 1572491507.
- "Philosophy in the Eighteenth-Century Dissenting Academies of England and Wales" (p.75-122) in Volume XI of History of Universities. Ed. Laurence Brockliss. Oxford University Press, 1993. ISBN 0198220014.
- Mill on God: the Pervasiveness and Elusiveness of Mill's Religious Thought. Ashgate Publishing, 2004. ISBN 0754616665.
- Testimony and Tradition: Studies in Reformed and Dissenting Thought. Ashgate Publishing, 2005. ISBN 0754640825.
- Confessing and Commending the Faith: Historic Witness and Apologetic Method. Wipf & Stock Publishers, 2006. ISBN 1597528722.
- Anna M Robbins. Ecumenical and Eclectic: The Unity of the Church in the Contemporary World: Essays in Honour of Alan P. F. Sell. Wipf & Stock Publishers, 2007. ISBN 1556354789.