"Historians often find important decisions few knew were important at the time." — Michael Beschloss

Too few presidents have steeped themselves not just in Lincoln's words but his deeds, which is why Obama's acquaintance with the great man is so compelling - especially since, like President-elect Lincoln, Obama will take office at a perilous time.

Mrs. Johnson was one of our most important First Ladies. Quietly but firmly, she advised LBJ on rhetoric, strategy, and personal relations and helped to dampen his volatile mood swings.

Troubled celebrities are a dime a dozen.

Historians sometimes view presidents very differently from the way the public did at the time. Sometimes they don't.