Heselton has been described by Allen Watkins, son of Alfred Watkins, as the person who "...led the post-war revival of academic and practical interest in Leys". In 1962, Heselton and others collaborated to form the Ley Hunters' Club, a revival of Alfred Watkins' Straight Track Club. The Ley Hunters worked on a hypothesis that Ley lines were not just prehistoric trackways, but were in some way connected with UFOs. Heselton edited the first issues of the club's journal, The Ley Hunter, in 1965-66 and frequently contributed articles to the journal when it reappeared between 1969 and 1976.

During this period Heselton's writing moved away from the speculation of the Earth mysteries such as ley lines and UFOs, and towards subjects more rooted in landscape, folklore, literature and local history. These covered subjects as diverse as dewponds, trees and sacred sites.

Since 2000, Heselton's publications have all centred around the origins of Wicca and its populariser (or inventor) Gerald Gardner. One review says of Heselton that "...he has dug deeper than anyone before him into the life and associates of Gerald B. Gardner ... No historian of Wicca's beginnings has conducted such patient and detailed research into primary sources. Heselton's view of Gardner is that he genuinely did make contact with a group who were maintaining remnants of an 'Old Religion', into which he was initiated in 1939 much as he describes. Many reviewers have greeted his work enthusiastically, treating it as a vindication of traditional accounts of Wiccan origins. Others have been less enthusiastic, describing the work as speculative. A more critical account of the origins of Wicca was previously provided by Ronald Hutton but the relationship between the two appears warm: Hutton has written in the foreword to Gerald Gardner and the Cauldron of Inspiration: "Philip Heselton is the most interesting, valuable and enjoyable author who has yet written on what is becoming one of the greatest riddles in the history of modern religion: the origins of pagan witchcraft".

• With Jimmy Goddard and Paul Baines: Skyways and Landmarks Revisited (1985)
• With Brian Larkman: Earth Mysteries - An Explanatory Introduction (1985)
• Tony Wedd: New age pioneer (1986). Northern Earth Mysteries. ISBN 0948635010
• The Elements of Earth Mysteries (1994). Element Books. ISBN 1852302283
• Secret Places of the Goddess: Contacting the Earth Spirit (1995). Capall Bann Publishing. ISBN 1898307407
• Mirrors of Magic: Evoking the Spirit of the Dewponds (1997). Capall Bann Publishing. ISBN 1898307849
• Leylines - A Beginner's Guide (1999). Hodder Arnold. ISBN 0340743166
• Magical Guardians: Exploring the Spirit and Nature of Trees 2nd revised edition. (1999). Capall Bann Publishing. ISBN 1861630573

• Wiccan Roots: Gerald Gardner and the Modern Witchcraft Revival (2000). Capall Bann Publishing. ISBN 1861631103
• Gerald Gardner and the Witchcraft Revival: The Significance of His Life and Works to the Story of Modern Witchcraft (2001). I-H-O Books. ISBN 1872189164
• Gerald Gardner and the Cauldron of Inspiration: An Investigation into the Sources of Gardnerian Witchcraft (2003). Capall Bann Publishing. ISBN 1861631642