I was looking at a graphic on the glass partition in our office when my thoughts turned to Stanislav Petrov. Petrov was a lieutenant colonel in the Soviet Air Defence Forces who played a key role in the 1983 Soviet nuclear false alarm incident. On September 26, 1983, three weeks after the Soviet military had shot down Korean Airlines Flight 007, Petrov was the duty officer in charge of the early-warning system which reported that the United States had launched six missiles. Petrov judged the alarm to be false based on the reasoning that a missile attack by the US would involve hundreds of missiles, not just six. His decision to disobey orders, against Soviet military protocol, prevented a retaliatory