- The Books of the Celts (6 books, 1987-1989)
Historical Fiction
- The New Europeans (1990)
- The Children of the Storm (1992)
- Out of the Mist (1995)
- Into the Fire (1997)
- Beyond the Sea (1999)
- Through the Gates (2001)
- To All Eternity (2004)
- Through the Desert (2006)
- Across the Waters (2009)
- In the Land of the Gods (2011)
- On the Edge of the Abyss (2014)
- On the Wings of the Storm (2016)
Science Fiction
- The New Europeans (1990)
- The Children of the Storm (1992)
- Out of the Mist (1995)
- Into the Fire (1997)
- Beyond the Sea (1999)
- Through the Gates (2001)
- To All Eternity (2004)
- Through the Desert (2006)
- Across the Waters (2009)
- In the Land of the Gods (2011)
- On the Edge of the Abyss (2014)
- On the Wings of the Storm (2016)
Other
- The Real Merlin: A Search for the True Sorcerer (2007)