Former President Herbert Hoover wrote a critique of his successor, Franklin D. Roosevelt, and of American foreign policy that he called his "magnum opus." This exhaustive review covered the years from 1933 through the early 1950s -- and remained unpublished for nearly 50 years. Hoover's biographer, George Nash, edited the manuscript and published it under the title, "Freedom Betrayed: Herbert Hoover's Secret History of the Second World War and Its Aftermath." Nash spoke about Hoover and his manuscript at the National Archives.