Book excerpt: In this essential new volume, Peter Jennings and Todd Brewster, the bestselling authors of The Century, take readers on a journey through the United States, and into the great themes of American identity. In Search of America explores the most controversial and liveliest debates of the day, and then moves back in time to the earliest days of the country's founding, to answer this central question: How have the ideals and principles on which the United States was founded served us -- have they withstood the inexorable march of time?