During World War II, British intelligence agencies sent operatives into occupied Europe to place some 16,000 homing pigeons carried in special containers. Most of the birds were never seen again, in some cases lost to hawks sent by the Germans to intercept them. But about ten percent returned, enough to make the effort worthwhile. The aim was to persuade any local people who chanced on the birds to write messages, hopefully containing intelligence on German military positions and movements, on tiny pieces of rice paper stuffed into a canister clipped onto each pigeon’s leg. As so often in wartime British intelligence, the project was handled by a collection of “oddballs and professors” and suffered from bureaucratic infighting, but it still made a difference. Corera’s vivid account shows how the pigeons’ messages revealed daily life under the Nazis and valuable intelligence. Some of the most useful information, including details of German positions and an assessment of recent British air raids, came from a Belgian network known as Leopold Vindictive, which was led by Father Joseph Raskin, a priest with intelligence experience from the previous war. In the end, Raskin was betrayed and caught and executed by the Germans.