When historian Lonnie Bunch was offered the position of founding director of the National Museum of African American History and Culture, he tried to talk himself out of it. The museum had no staff or collection -- just the daunting mission to document the African American experience and help the nation understand its dark history of slavery. Bunch took the job, and his new book "A Fool's Errand" recounts his work on what he calls his life's "grandest challenge." Last June, Bunch was appointed Secretary of the Smithsonian Institution. He joins us to discuss his book and the contributions he’s made in preserving American history.