This is highly recommended viewing for those people trying to understand how it is that the truth of certain events, like 9/11, can be so successfully spun into something completely different by the people who want to make it so.
In this 8-part series Dr. William F. Pepper leads the co-publisher of Covert Action Quarterly, William Schaap, through a history of US Government Approved disinformation, beginning with examples in WWI and then WWII, when things really began to take off. The techniques of disinformation that the government employed during war-time were carried over into peace-time under the aegis of the Cold War. Schaap sites specific examples of CIA and FBI disinformation, concluding with Hoover’s FBI attacks on Dr. Martin Luther King, Jr.
Transcript: (scroll down to approx. 3/4 down page)