Glenn Beck recommends the writings of former FBI Special Agent (and John Birch Society endorser and JBS speaker) W. Cleon Skousen.
See: http://www.salon.com/news/feature/2009/ ... index.html
In fact, Glenn Beck wrote the "Foreward" to the 2009 edition of Skousen's best-selling book, The 5000 Year Leap
http://www.skousen2000.com/political%20 ... ousand.htm
However, both Cleon Skousen (and his admirers) have misrepresented Skousen's FBI background and inflated his credentials.
Some, like the John Birch Society, claim that Skousen was a "top aide" to J. Edgar Hoover [See, for example, JBS Bulletin, January 1968, page 1] OR an "administrative assistant" to Hoover.
Others claim that Skousen had extensive investigative experience while he served in the FBI -- particularly with respect to internal security-related matters.
But ALL of these claims are utter falsehoods.
Furthermore, senior FBI officials expressed very derogatory judgments about Skousen's post-FBI endeavors.
In fact, they scornfully described him as someone who allied himself with "professional anti-communists" who represented the "extreme right" in our country and FBI officials thought Skousen was mis-using his FBI service to falsely claim expertise in subject matters which he did not possess.
For a detailed 26-page report (recently updated) on Skousen which is based, primarily, upon his FBI personnel file, see:
http://ernie1241.googlepages.com/skousen