Knopf announced Monday that it will publish a biography of Barack Obama by New Yorker editor David Remnick that charts the president's evolution from a confused, biracial young man to an icon of hope. "The Bridge: The Life and Rise of Barack Obama" will be released April 6. Remnick is the author of "Lenin's Tomb," the Pulitzer Prize-winning tale of the collapse of the Soviet Union, and of "King of the World," the story of Muhammad Ali during the civil-rights movement. The Obama biography relie...