The author of the Pulitzer prize-winning "Titan: The Life Of John D. Rockefeller, Sr." applies the same depth of biographical engagement to Union hero of the American Civil War Ulysses S. Grant, contextualising Grant's military genius against a pre-war life characterised by personal defeats, and looking in fresh detail at Grant's two terms as president. Leonardo Di Caprio has bought rights and financed a potential Grant biopic.