(Note: This interview first aired back in February.) Very early in her career, the well-regarded American colonial historian Mary Beth Norton came to believe that the critical year in American independence was not 1776, but rather, 1774. Yet her academic focus on women's colonial history sidelined her interest in fleshing out this theory. Now, the author of such critical women's histories as "In the Devil's Snare" and "Separated by Their Sex" has returned to this initial thesis with her newest book, "1774: The Long Year of Revolution." In this pivotal 17-months period, from the Boston Tea Party, in December 1773, to the first shots at Lexington and Concord, in April 1775, Norton argues, an evolution in thinking occurred throughout the 13 colonies -- a shift from a prevailing loyalty to Great Britain to an emerging viewpoint that British rule must change, or else war would be inevitable.