Financial Times
Feb 27, 2023 - 6 min
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A brief history of secret communication methods, from invisible ink to tattooed heads
11 mins | Apr 30, 2023
Secret communication is at the heart of espionage operations and essential for successful spy work. In this extract from Kristie Macrakis's book "Espionage: A Concise History", discover the ancient communication techniques still employed by agents today.
