MARK IV MICRODOT CAMERA

When the Berlin Wall was erected, passing documents between agents in Eastern Europe and the West became nearly impossible. The mail became the primary means of communication, and many agents relied on "microdots" to get messages through. Using a microdot camera -- itself small enough to be used undetected -- an agent could take photographs that could be reduced to a tiny dot. The pinhead-sized piece of film was then glued somewhere in a typewritten letter and sent through the mail undetected . The agent receiving the letter would retrieve the film and put it under a microscope to read the message. Microdot cameras were used primarily during the 1950s and early 1960s.