Trevor Paglen

"With the beginning of the War on Terror, the CIA set up a network of secret prisons in Afghanistan and elsewhere around the world. Hundreds of ‘ghost prisoners’ have gone through this system. The black sites have become synonymous with allegations of torture. The locations of the secret prisons have been some of the Bush Administration’s most closely-guarded secrets."[1]

After some browsing around the internet I stumbled upon Trevor Paglen. His work uncovers and revolves around the theme of secrecy and in particular the CIA or other American secret organisations.
I became aware of his 'Black Sites' project first, which is where the above quote is from. Information and imagery is sparse about this project but as such so is the subject matter on which it focuses.

 The Salt Pit, Northeast of Kabul, Afghanistan

Black Site, Kabul, Afghanistan 

Another project of his is 'Limit Telephotography', a project whereby he has used telescopes and methods more used to astrophotography to photograph secret sites and installations housed in the middle of nowhere, miles from anything. The resulting imagery are blurry and what you would expect from long telephoto lenses, however these photos have been taken from miles away.

Taken from a distance of 1 mile.

Morning Commute, ‘Gold Coast’ Terminal, Las Vegas, Nevada, 2006

Taken from a distance of 26 miles.
Detachment 3, Air Force Flight Test Center #2, Groom Lake, Nevada, 2008

There is a book that accompanies this series of work entitled 'Invisible: Covert Operations And Classified Landscapes, by Trevor Paglen' published by Aperture.

Trevor Paglen visits Google's Mountain View, CA headquarters to discuss his book "Blank Spots on the Map: The Dark Geography of the Pentagon's Secret World." Feb 11, 2009

Sources:
Guardian Report
Trevor Paglen
[1]
Further Reading:
Extraordinary Rendition, Black Sites, Secret CIA Prisons, Trevor Paglen and Telephotography
Invisible: Covert Operations and Classified Landscapes, Photographs by Trevor Paglen
Trevor Paglen : Odd and Ends Blog
Logos offer a guide to secret military research
Mapping the Black Sites