- The City: A Novel (2004)
- City of Shadows: A Novel (2005)
- City of Light: A Novel (2006)
- The Secret History of the Third Reich (2008)
- The Dogs of War: A Novel (2009)
- The Last Battle: A Novel (2010)
Non-fiction:
- The Nazi Underground in America (1993)
- Secret Societies and the Power Elite (1994)
- The Illuminati: A History (1995)
- The New World Order: A History (1996)
- The End of the World: A History (1997)
- The Anti-Christ: A History (1998)
- The 13th Step: A History of Secret Societies (1999)
- The Freemasons: A History (2000)
- The Knights Templar: A History (2001)
- The Rosicrucians: A History (2002)
- The Holy Grail: A History (2003)