Jeremy Scahill's important book, Blackwater: The Rise of the World's Most Powerful Mercenary Army...

http://www.amazon.com/Blackwater-Rise-Worlds-Powerful-Mercenary/dp/1560259795


Here's an excellent talk by Scahill on the subject of his book...

http://fora.tv/2008/06/13/Jeremy_Scahill_Blackwaters_Covert_Rise_to_Power