The first half of A Short Course in the Secret War describes US intelligence policies, developed during WWII and expanded during the Cold War, with the second half describing the author's experiences in Hungary prior to Soviet takeover.
The ideas remain valid in 2020 - "the cardinal rule of such operations - do not make unnecessary promises or promises you have neither the ability nor intention to keep. Once a promise is given, an agreement made, it must be kept to the best of one's ability. In the jungle of international politics this is the equivalent of 'honor among thieves'."