His major works during this period included: "Grover Cleveland: A Study in Courage" (1932, which won his first Pulitzer Prize), "History of the Bank of New York and Trust Company, 1784–1934" (1934), "Hamilton Fish: The Inner Story of the Grant Administration" (1936, which won his second Pulitzer Prize), "The Gateway to History" (1938), a two-volume biography of John D. Rockefeller, "The Heroic Age of American Enterprise" (1940; rewritten and expanded as "A Study in Power: John D. Rockefeller, Industrialist and Philanthropist" in 1953).