|Historians continue to debate the legacy of the two-term presidency of Ronald Reagan, who recently celebrated his 90th birthday. The only thing almost everyone agrees on is that Reagan lived a remarkable life. He moved with apparent ease from a small-town boyhood in the Midwest to stardom in Hollywood to the nation's chief executive. The strength and optimism he projected as president, tempered by his enormous good humor, made him a popular leader. Despite his smiling, affable demeanor, he was a complex loner who kept even his closest advisers at arm's length.