| Title | Titolo | Year | Series | Note |
| The Wind from Hastings | 1978 | |||
| Lion of Ireland: The Legend of Brian Boru | 1979 | |||
| The Horse Goddess | 1982 | |||
| Bard: The Oddyssey of the Irish | 1984 | |||
| Grania: She-King of the Irish Seas | 1986 | |||
| Xerxes | 1987 | |||
| Princess | 1987 | |||
| The Red Branch | 1989 | |||
| The Isles of the Blest | 1989 | |||
| On Raven's Wing | 1990 | |||
| Brian Boru: Emperor of the Irish | 1990 | |||
| Druids | 1991 | |||
| The Last Prince of Ireland | 1992 | |||
| O'Sullivan's March | 1992 | |||
| Strongbow: The Story of Richard and Aoife | 1992 | |||
| All Hallow's Eve | 1992 | |||
| The Elementals | Il potere degli elementi | 1993 | ||
| Star Dancer | 1993 | |||
| Finn Mac Cool | 1994 | |||
| Silverhand | 1995 | Arcana | ||
| Irish Magic | 1995 | |||
| Angels of Darkness | 1995 | |||
| The Best of Weird Tales | 1995 | |||
| Untitled | 1995 | |||
| Silverlight | 1996 | Arcana | ||
| Pride of Lions | 1996 | |||
| 19 Railway Street | 1996 | |||
| The Vikings in Ireland | 1996 | |||
| Don't Forget Your Spacesuit, Dear | 1996 | |||
| The Resurrected Holmes: New Cases from the Notes of John H. Watson | 1996 | |||
| The Repulsive Story of the Red Leech | 1996 | |||
| Your Face Will Freeze Like That | 1996 | |||
| Cold Places | 1997 | |||
| Irish Magic II: Four Unforgettable Novellas of Love and Enchantment | 1997 | |||
| 1916: A Novel of the Irish Rebellion | 1998 | 1998 RIO Award | ||
| Etruscans | 1999 | Beloved of the Gods | ||
| Royal Whodunnits | 1999 | |||
| Woman in a Wheelchair | 1999 | |||
| The Earth is Made of Stardust | 2000 | |||
| A Pocket History of Irish Rebels | 2000 | |||
| 1921 | 2001 | |||
| Granuaile | 2001 | |||
| 1949 | 2003 | |||
| 1972: A Novel of Ireland's Unfinished Revolution | 2005 | |||
| The Greener Shore: A Novel of the Druids of Hibernia | 2006 | |||
| Pirate Queen | 2006 | |||
| The Young Rebels | 2006 | |||
| 1999: A Novel of Ireland And the Search for Peace | 2007 |