''Off We Go Into the Wild Blue Bunko...''

''Air Force PSYOP forces support US national and military objectives through planned operations to convey information to target audiences. PSYOP provide a low-cost, high-impact method to deter adversaries and obtain the support of friendly or neutral target audiences. The effective use of PSYOP can provide asymmetrical advantages by exposing and exploiting adversaries’ resistance and psychological weaknesses to create uncertainty and ambiguity, thereby lowering their morale and will to fight and win. In combination with military operations, PSYOP can encourage popular discontent with the adversary’s leadership and degrade the enemy’s ability to conduct military operations.''

Psychological Operations (USAF, 1999)

https://archive.org/details/PsychologicalOperations_201502

''Did you hear THAT?''

Unusual Investigative Techniques (F.B.I., 1961)

https://archive.org/details/foia_FBI_Monograph-Unusual_Investigative_Techniques

''Spy vs Spy''

Some transcripts from ''Venona'', a U.S. counter-intelligence program that lasted from 1943 to 1980 to decrypt messages sent by Soviet intelligence.

Venona program documents (N.S.A. , published 1995)

https://archive.org/stream/foia_Venona-HQ-1/Venona-HQ-1#page/n65/mode/2up