To a whole generation of Americans, President Franklin Delano Roosevelt was the most accessible of figures. Millions felt intimately familiar with all the details of his life: his wife Eleanor, his Scottish Terrier Fala, his cigarette holder, his stamp collection. Yet F.D.R.'s Treasury Secretary Henry Morgenthau Jr. described him as simultaneously evasive and frank, frivolous as well as grave, "a man of bewildering complexity." The playwright Robert Sherwood, who served for years as the President's speechwriter, admitted that he had never been able to penetrate Roosevelt's "heavily forested interior."
Geoffrey Ward, former editor of American Heritage, is the latest of many...