The Tale of the Tub: A Survey of the Art of Bathing Through the Ages, Newman Neame, 1950
King Arthur's Avalon: The Story of Glastonbury, Collins, 1957
From Caesar to Arthur, Collins, 1960
Land to the West: St. Brendan's Voyage to America, Collins, 1962
The Land and the Book, Collins, 1965
The Carmelite Order, Carmelite Press, 1965
Gandhi: A Study in Revolution, Stein & Day, 1968
(Editor and contributor) The Quest for Arthur's Britain, Pall Mall, 1968
King Arthur in Fact and Legend, T. Nelson, 1971
Camelot and the Vision of Albion, Heinemann, 1971
(With others) The Quest for America, Pall Mall, 1971
The Art of Writing Made Simple, W. H. Allen, 1972
The Finger and the Moon (a novel), Heinemann, 1973
Do What You Will: A History of Anti-morality, W. H. Allen, 1974
The Virgin, Routledge & Kegan Paul, 1976
The Ancient Wisdom, Macmillan, 1977
Miracles, Routledge & Kegan Paul, 1978
A Guidebook to Arthurian Britain, Longman, 1980
Kings and Queens of Early Britain, Methuen, 1982
Avalonian Quest, Methuen, 1982
The Discovery of King Arthur, Doubleday, 1985
The Landscape of King Arthur, Webb & Bower, 1987
(With Norris Lacy) The Arthurian Handbook, Garland, 1988
Mythology of the British Isles, Methuen, 1990
King Arthur: The Dream of a Golden Age, Thames & Hudson, 1990
Dawn Behind The Dawn,Henry Holt, 1992
Atlantis, Thames & Hudson, 1992
