What is the main theme in the novel, The Last Heroes?

Secrecy is a theme that runs throughout the book. Everyone is keeping secrets from everyone else—Allies from Germans, neutrals from Germans; Roosevelt from his staff, and individuals from each other. These secrets are on the national, organizational, and personal levels. Roosevelt does not seem to confide in J. Edgar Hoover, FBI director; the American Volunteer Group (the famous Flying Tigers) is a secret entity drawn from the ranks of the Navy and Army Air Corps.