Everything you need to know about U.S. spying operations ...

 

The folks over at ProPublica have compiled an extraordinary  package of stories and graphs, from past and present, that explain the NSA’s surveillance program as well as other wiretapping efforts used by law enforcement agencies in the U.S. They have also created a timeline of U.S. spying techniques dating  back to the 1978 Church hearings, which led to the creation of the FISA court.

You can read the material here, here and here.