Introduction -- The evolution of American obscenity regulation and the FBI : the 1830s to 1932 -- The development of a centralized Obscene File : the 1940s -- The postwar Obscene File and social regulation : the late 1940s and 1950s -- Changing judicial views on obscenity, the Nixon administration, and the FBI : 1957 to the early 1970s -- The FBI's anti-obscenity undercover operations : the 1970s and 1980s -- The end of the Obscene File and the temporary revival of the FBI's role in adult obscenity -- Conclusion.