For many the postcard may seem trivial, little more than a mundane souvenir or a way to keep in touch with friends and relatives while on vacation. But if we look carefully, postcards offer valuable insights into the time periods in which they were created and the mentalities of those who bought or sent them. Frank Marhefka, while serving in the U.S. Army Motor Transportation Corps during the First World War, amassed a collection of more than 150...