The Tolkachev story is based, in part, on 944 pages of declassified CIA operational files, primarily cable traffic between headquarters and Moscow station from 1977 to 1985.
Here I have posted a sampling of the cables cited in the Notes. Each carries a time-date stamp, and the format is as follows: the first two digits are the date, the next four are the time in GMT that the cable was sent, followed by a Z, such as 131423Z for a cable sent on the thirteenth at 2:23 p.m. GMT. Some pages and sections of pages are blank. The documents were reviewed by the CIA for information considered sensitive, and that information was redacted prior to release to me. The CIA placed no restrictions on my use of the documents, nor did the agency review the manuscript prior to publication.