The Central Intelligence Agency (CIA) maintains a very high quality records system called ARCINS, the Agency Records and Information System. ARCINS contains subject listings down to the folder level of more than 34 million records.
Requesters seeking records under either the Freedom of Information Act (FOIA)or under the provisions of Mandatory Declassification Review can specify a search of ARCINS when contacting the CIA. Such a request will aid the agency in processing requests more efficiently.
If you wish to submit a request, simply identify the relevant keywords and submit a request to the following address, asking that the agency conduct a search of ARCINS.
Source and more information: Cryptome