This book sheds light on Japanese intelligence and propaganda activities in the United States prior to Pearl Harbor, Japanese attempts to use American isolationists and pacifists in 1941, and Japanese and American efforts to save Emperor Hirohito from being tried as a war criminal during the U.S. occupation of Japan. It utilizes the American cracking of the Japanese diplomatic code, FBI surveillance and wiretapping records, and the personal papers of Americans with whom Terasaki Hidenari had contact to conclude that he wanted peace between the United States and Japan in 1941 and worked to preserve the imperial institution following the war.