The Passport Invisible is a novel written by Perley Poore Sheehan and published in 1917. The story revolves around a young American man named John Delmont who, after being falsely accused of a crime, decides to flee to Europe to start a new life. However, he soon finds himself embroiled in a web of espionage and intrigue, as he becomes entangled with a group of spies who are trying to obtain a secret formula for a powerful explosive.As Delmont navigates...