Katie McBride Moench writes: “In war, as in everything, information is power. And for the US and its allies in World War II, that meant obtaining and transmitting by hand useful intel—like the development of destructive new weapons—before the Nazis could prevent their enemies from getting it. Enter the librarians, tapped by US government officials to help in this effort. These librarians adopted technology from other fields to photograph an array of documents and found means of sending them across continents.