In four short years, James K. Polk transformed the United States into a coast-to-coast behemoth. Through diplomacy, war, and relentlessness, Polk achieved every major agenda item he set out to accomplish, and yet somehow he has fallen short of the mythical status of other presidents -- even less accomplished ones. Tony Rydberg and Ryan Rasmussen explore the administration of James K. Polk, a president who, more than any other, embodies the American obsession with stretching itself from sea to shining sea: an obsession named "Manifest Destiny."