Seminal Work for the Middle Period of Intelligence,
Sherman Kent was without question the dean and the prophet for the second era, and this gem of a book remains a standard in the field and required reading for any intelligence professional (collector, analyst, or other). He did not realize his vision because the clandestine service (of which I was a member) took over the CIA and subordinated the analysts, and because in so doing, the CIA lost touch with most of the open source world.
Today Kent is succeeded by Jack Davis, whose term “analytic tradecraft” can be used to find his collection of memos on the web, and by the CIA University. However, the secret world is now under attack by the emergent World Brain, in which Collective (Public) Intelligence utilizes open sources of information to create Open Source Intelligence (OSINT) that is better than secret information, cheaper than secret information, and more useful than secret information because it can be shared broadly.
Those whose sense of self is defined by the secret world will have difficulty adjusting to this, witness the continued references in the secret world to “Open Sources.” Max nix. The war is over, and Kent’s vision will ultimately be realized in the third era, the era of open sources.