The policies and persona of Franklin Roosevelt set the cast of the "modern" presidency. He was unquestionably the most vital figure in the nation, and perhaps the world, during his 13 years in the White House. Engendering both admiration and scorn, FDR exerted unflinching leadership during the most tumultuous period in the nation's history since the Civil War -- implementing the New Deal programs during the Great Depression and intervening in the Second World War. Learn more with this biography from American Experience: "The Presidents."