Виктор Суворов
Oleg Penkovsky, a double agent in the Soviets' GRU intelligence service working for the Central Intelligence Agency and Britain's MI6, provided details of the missile placements to the United States. A former GRU colonel who defected, Viktor Suvorov, wrote, "Historians will remember with gratitude the name of the GRU Colonel Oleg Penkovsky. Thanks to his priceless information, the Cuban crisis was not transformed into a last World War."