Clandestine services history

The Central Intelligence Agency has released a newly declassified version of its closely-held internal history of the Berlin Tunnel Operation (pdf), which was an effort in the mid-1950s to tap into Soviet communications through a tunnel constructed in the Soviet sector of Berlin. The operation was famously compromised by a Soviet mole in British intelligence before it even began. The official CIA history of the operation was prepared in 1968 and published -- in two copies. A declassified version was finally approved for release in February 2007.