Barack Obama's journey from community organizer in Chicago to the presidency has been extraordinary. A teacher in Mississippi recognized his potential early on and had students remember his name. On Tuesday, Obama will be sworn in as the 44th President, using Abraham Lincoln's Bible. His exotic childhood, time as a legislator in Illinois, and improbable rise to the U.S. Senate and presidential candidate are now familiar mileposts in his path to becoming the most powerful man in the world.