Came across this - CIA Project Treasure Island from the 40/50's. It seems to deal with the gathering of intelligence from open source documents.

"It is believed that, within a few years,  it will be possible to say: Never before was so much intelligence gained from so small a cost. "

https://www.cia.gov/library/readingroom/document/cia-rdp81-00706r000100230040-2