While investigating, Woodward and Bernstein had a critical source, Deep Throat. “Woodward had a source in the Executive Branch who had access to information at the CRP as well as at the White House. His identity was unknown to anyone else. He could be contacted only on very important occasions. Woodward had promised he would never identify him or his position to anyone. Further, he had agreed never to quote the man, even as an anonymous source. Their discussions would be only to confirm information that had been obtained elsewhere and to add some perspective. In newspaper terminology, this meant the discussions were on ‘deep background.’...[Howard] Simons dubbed him ‘Deep Throat’...The name stuck.” 
Felt’s identity as Deep throat was confirmed 30 years later in a Vanity Fair article in 2005, “Despite three decades of intense speculation, the identity of ‘Deep Throat’—the source who leaked key details of Nixon's Watergate cover-up to Washington Post reporters Bob Woodward and Carl Bernstein—has never been revealed. Now, at age 91, W. Mark Felt, number two at the F.B.I. in the early 70s, is finally admitting to that historic, anonymous role.”  Felt’s initial agreement to give information came after being denied the job of director, which Nixon had given to an FBI outsider instead. 
- Header Image: Tim Weiner, "W. Mark Felt, Watergate Deep Throat, Dies at 95," The New York Times, December 19, 2008, [Page #], accessed February 3, 2017, http://www.nytimes.com/2008/12/19/washington/19felt.html.
- Carl Bernstein and Bob Woodward, All the President's Men (New York, NY: Carl Bernstein and Bob Woodward, 1974), 71.
- John D. O'Connor, "I'm the Guy They Called Deep Throat," Vanity Fair, July 2005, accessed January 30, 2017, http://www.vanityfair.com/news/politics/2005/07/deepthroat200507.
- David Von Drehle, "FBI’s No. 2 Was ‘Deep Throat’: Mark Felt Ends 30-Year Mystery of the Post’s Watergate Source," The Washington Post, June 1, 2015, accessed January 13, 2017, https://www.washingtonpost.com/politics/fbis-no-2-was-deep-throat-mark-felt-ends-30-year-mystery-of-the-posts-watergate-source/2012/06/04/gJQAwseRIV_story.html?utm_term=.686e87fcd9c4.
- Harry Ransom Center, "Deep Throat Exposed," Harry Ransom Center: The University of Texas at Austin, accessed February 5, 2017, http://www.hrc.utexas.edu/exhibitions/web/woodstein/deepthroat/felt_notes5_1_large.html.
- O'Connor, "I'm the Guy They,".