Summary of Nathaniel Philbrick's Valiant Ambition focuses on the treachery of Benedict Arnold as it plays out against the wider panorama of the American Revolution.

Benedict Arnold was a courageous officer who was responsible for a number of crucial American victories during the Revolution. His brilliant conduct of the Battle of Valcour Island at Lake Champlain in 1776 delayed British forces and prevented them from reaching the Hudson River valley. Had the British succeeded, they might have separated New England from the rest of the colonies and quickly ended the war. Arnold also managed the American victory at the Battle of Freeman's Farm, which helped ensure the defeat of British General John Burgoyne at the Battle of Saratoga in upstate New York. That battle, in turn, encouraged the French to enter the war, which made the ultimate American victory possible...