Yardley's book (annotated by his arch rival Friedman no less!) referenced in the NSA document is here: https://archive.org/details/AmericanBlackChamber https:/

Yardley's book (annotated by his arch rival Friedman no less!) referenced in the NSA document is here: https://archive.org/details/AmericanBlackChamber https://archive.org/details/AmericanBlackChamber "The cryptography historian David Kahn called the book "the most famous book on cryptology ever published."