NSA publishes history of computers used by the agency until 1964
One of the most secret US secret agencies, the NSA ( National Security Agency ), opened a book about the history of the earliest use of computers within the agency until 1964. That is, it talks about how ATLAS , the early machines from IBM and UNIVAC , were created and used .
Link to material: http://www.governmentattic.org/3docs/NSA-HGPEDC_1964.pdf
The text is rather large (a little over 100 pages), but very complete and interesting. I advise.
PS: For example, it is interesting to read how the memory of the ABNER machine was arranged: on acoustic waves in mercury.