23 November 2020
Espionage has been called the second oldest profession, and with good reason. Sun Tzu's The Art of War, a famous textbook on waging an effective war, devoted a great deal of significance to espionage and the creation of a secret spy network. All warfare is deception, he stated, and "Be subtle! Be subtle!" he intoned, and "use your spies for every kind of business." It was published in 510 BC.
