John D. Marks, a former State Department employee, made the Register
famous in his article "How to Spot a Spook" in Washington Monthly, November
1974. It turns out that CIA officers posted abroad under State Department
cover tend to drop in and out of this annual publication with certain
characteristics in their listings. Because this was so useful, the 1974
edition was the last one distributed to the public. We went through a 1977
"limited official use" edition (the latest we can get our hands on), and
then the unclassified 1973 and 1969 editions. Out of these we ended up
with a total of almost 3400 names. About half are CIA officers, while the
rest are either with the State Department and at some point in their career
may have specialized in intelligence, or were with AID's Office of Public
Safety. (Before Congress phased it out in 1974, OPS was used by the CIA
for official cover.) We already had most of the CIA names, but the Registers
gave us better posting data for our nifty country graphs. The classification
of this Register is a loss for human rights researchers everywhere.
-- D.Brandt
Extract the names from this source