Thomas Cahill is the author of a series of books detailing turning points in Western civilization and the impact of various cultural heritages. These books include How the Irish Save Civilization: The Untold Story of Ireland's Heroic Role from the Fall of the Roman Empire to the Rise of Medieval Europe and The Gift of the Jews: How a Tribe of Desert Nomads Changed the Way Everyone Thinks and Feels. Before embarking on his ambitious series, which will eventually include seven volumes, Cahill was the director of religious publishing at Doubleday.