- _The Endless Train_ (1989)
- _The Heroes of the Revolution_ (1989)
- _The Time Trap_ (1990)
- _The Magic Circle_ (1991)
- _The Secret of Dreadwillow Castle_ (1992)
- _The Dragon's Eye_ (1993)
- _The Ghost of Thomas Kempe_ (1994)
- _The Curse of the Silver Pharaoh_ (1995)
- _The Riddle of the Seventh Stone_ (1996)
- _The Key to the Lost Kingdom_ (1997)
- _The Crystal Skull_ (1998)
- _The Firebird's Feather_ (1999)
- _The Sword of the Samurai_ (2000)
- _The Sorcerer's Apprentice_ (2001)
- _The Alchemist's Daughter_ (2002)
- _The Book of Shadows_ (2003)
- _The Amulet of Power_ (2004)
- _The Seventh Crystal_ (2005)
- _The Ring of Solomon_ (2006)
- _The Staff of Moses_ (2007)
- _The Ark of the Covenant_ (2008)
- _The Spear of Destiny_ (2009)
- _The Holy Grail_ (2010)
- _The Shroud of Turin_ (2011)
- _The Crown of Thorns_ (2012)
- _The Last Supper_ (2013)
- _The Resurrection_ (2014)
- _The Ascension_ (2015)
Non-Fiction:
- _The Time Traveler's Guide to Medieval England_ (1995)
- _The Time Traveler's Guide to Ancient Egypt_ (1996)
- _The Time Traveler's Guide to Renaissance Italy_ (1997)
- _The Time Traveler's Guide to Victorian London_ (1998)
- _The Time Traveler's Guide to the Wild West_ (1999)
- _The Time Traveler's Guide to the Age of the Dinosaurs_ (2000)
- _The Time Traveler's Guide to the Future_ (2001)
- _The Time Traveler's Guide to the Solar System_ (2002)
- _The Time Traveler's Guide to the Universe_ (2003)
- _The Time Traveler's Guide to the History of Science_ (2004)
- _The Time Traveler's Guide to the History of Technology_ (2005)
- _The Time Traveler's Guide to the History of Medicine_ (2006)
- _The Time Traveler's Guide to the History of War_ (2007)
- _The Time Traveler's Guide to the History of Art_ (2008)
- _The Time Traveler's Guide to the History of Music_ (2009)
- _The Time Traveler's Guide to the History of Literature_ (2010)
- _The Time Traveler's Guide to the History of Philosophy_ (2011)
- _The Time Traveler's Guide to the History of Religion_ (2012)
- _The Time Traveler's Guide to the History of the World_ (2013)
- _The Time Traveler's Guide to the Future of the World_ (2014)