Editor of Making Eden Grow: An Anthology of Christian Poetry (Scripture Union, 1974)

Introduction by Colin Duriez: At the Back of the North Wind, George MacDonald, illustrated by Arthur Hughes

(Scripture Union, 1978)

Edited, with an introduction, by Colin Duriez:The Princess and the Goblin, George MacDonald (Scripture Union/ David C. Cook, 1978).

Edited, with an introduction, by Colin Duriez: The Princess and Curdie, George MacDonald (Scripture Union / David C. Cook, 1978).

Edited, with an introduction, by Colin Duriez: The Lost Princess, George MacDonald (Scripture Union / David C. Cook, 1978).

Edited, with an introduction, by Colin Duriez: The Golden Key and other Stories, George MacDonald (Scripture Union/ David C. Cook, 1978).

The C.S. Lewis Handbook (Monarch Publications / Baker Book House, 1990)

The Tolkien and Middle-earth Handbook (Monarch Publications / Baker Book House / Angus and Robertson, 1992)

The C.S. Lewis Encyclopedia, by Colin Duriez (Wheaton, Illinois: Crossway Books, 2000/SPCK, June 2002)

Edited, with an introduction, by Colin Duriez: The Diary of an Old Soul, George MacDonald (SPCK, 1978).

Compiled, with an introduction, by Colin Duriez, The Poetic Bible (SPCK/Hendrickson, 2001).

Co-authored with David Porter, The Inklings Handbook (Azure[SPCK]/Chalice Books, 2001).

Tolkien and The Lord of the Rings (Azure [SPCK]/HiddenSpring [Paulist Press, NY], 2001). Republished as A Guide to Middle-earth: Tolkien and The Lord of the Rings (Thrupp: Sutton Publishing

Introduction by Colin Duriez: Phantastes, George MacDonald, illustrated by Arthur Hughes (SPCK, June 2002).

Tolkien and C.S. Lewis: The gift of friendship/The story of their friendship (New York: The Paulist Press & Thrupp:Sutton Publishing, 2003).

A Field Guide to Narnia (Downers Grove, Illinois: InterVarsity Press, 2004 and Thrupp: Sutton Publishing, 2005).

The C. S. Lewis Chronicles: The Indispensable Biography of the Creator of Narnia Full of Little-Known Facts, Events and Miscellany (New York: Bluebridge and London: DLT, 2005).

AD 33: The year that changed the world (Thrupp: Sutton Publishing, March 2006—now The History Press, Stroud/Downers Grove, Illinois: IVP, 2006).

A Field Guide to Harry Potter (Downers Grove, Illinois: InterVarsity Press, 2007); Unauthorized Harry Potter Companion (Thrupp: Sutton Publishing, 2007—now The History Press, Stroud).

Francis Schaeffer: An Authentic Life (Wheaton, Illinois: Crossway Books, 2008; Nottingham: Inter-Varsity Press, 2008)

J. R. R. Tolkien: The Making of a Legend (Oxford: Lion Hudson, 2012).

Amazing and Extraordinary Facts: J.R.R. Tolkien (Newton Abbot, David & Charles, 2012; Exeter: Rydon Publishing, 2018).

C. S. Lewis: A Biography of Friendship (Oxford: Lion Hudson, 2013).

The A–Z of C.S. Lewis: An encyclopedia of his life, thought and writings (Oxford: Lion Hudson, 2013).

The Oxford Inklings: Lewis, Tolkien and Their Circle (Oxford: Lion Hudson, 2015).

Bedeviled: Lewis, Tolkien, and the Shadow of Evil (Downers Grove, Illinois: IVP, 2015).

Dorothy L. Sayers, A Biography: Death, Dante and Lord Peter Wimsey (Oxford: Lion Books, October 2020)