* *In the Wake of the Armada; England In 1588* (historical, 1933)
* *An Admiral Sails West* (non-fictional biography of George Vancouver, 1938)
* *Death Be Not Proud* (biographical study of Charles de Gaulle, 1943)
* *The Man Napoleon* (fictionalized biography, 1949)
* *From Martyr to Murderer* (study of Saint Teresa of Ávila, 1955)
* *Brother to Satan – Adolf Hitler’s Life (1889 – 1912)* (study on Hitler based on Austrian police records on his time in Vienna, 1977)
* *Hitler’s Fatal Year, Germany Prepares for World War II; Hitler’s War Begins* (fictionalized and revised biography, 1978)