Which "The Courier" is about: "The spy who saved the world : how a Soviet colonel changed the course of the Cold War : Schecter, Jerrold L : "

"The Spy Who Saved the World tells, for the first time, the complete story of the life and legendary career of the greatest spy of the Cold War, Oleg Penkovsky, the highest-ranking Soviet military official ever to cooperate with the West. At the height of the Cold War, during 1961 and 1962. Oleg Penkovsky provided the CIA and MI6, the British Intelligence Service, with unusually reliable data on Soviet military intentions and nuclear strength. This information, channeled.."

https://archive.org/details/spywhosavedworld00jerr