Standalone Novels:
ICE REICH (1998)
GETTING BACK (2000)
DARK WINTER (2001)
HADRIAN'S WALL (2004)
THE SCOURGE OF GOD (2005)
BLOOD OF THE REICH (2011)

Ethan Gage Adventures:
NAPOLEON'S PYRAMIDS (2007)
THE ROSETTA KEY (2008)
THE DAKOTA CIPHER (2009)
THE BARBARY PIRATES (2010)
THE EMERALD STORM (2012)
THE BARBED CROWN (2013)
THE THREE EMPERORS (2014)

Non-fiction:
THE FINAL FOREST (1992)
NORTHWEST PASSAGE (1995)
NATURAL GRACE (2003)
ON PUGET SOUND (2007)