Suspense, intrigue and betrayal – it’s all there in Nathaniel Philbrick’s true-life tale of America’s battle for independence. In “Valiant Ambition: George Washington, Benedict Arnold, and the Fate of the American Revolution,” Philbrick explores the brutal middle years of the war and the tragic relationship between Washington and Arnold, two men who fought passionately for the same cause – until one of them betrayed it.