Mark Fallon is a former Naval Criminal Investigative Service special agent and counter-terrorism expert from the United States.

[5] According to Ben Taub, writing in the New Yorker magazine, by August 2002 "Fallon's élite interagency criminal-investigation task force had been sidelined.

"[9][10][11] Fallon said that he faced significant resistance from the government in publishing his book, including extended delays and censorship of 113 passages, often for information that was already part of the congressional record.

The American Civil Liberties Union mounted a defense of Fallon's First Amendment right to free speech, and contacted several members of Congress.

[12] Fallon and Maria Hartwig, a psychologist at John Jay College of Criminal Justice at City University of New York, are developing a training curriculum for investigators based in actual science related to lying and deception.