A committee of the United States Intelligence Board concluded that the book was "a possibly valuable support to foreign COMSEC authorities" and recommended "further low-key actions as possible, but short of legal action, to discourage Mr. Kahn or his prospective publishers". Kahn's publisher, Macmillan and Sons, handed over the manuscript to the government for review without Kahn's permission on 4 March 1966. Kahn and Macmillan eventually agreed to remove some material from the manuscript, particularly concerning the relationship between the NSA and its counterpart in the United Kingdom, GCHQ.
