Skull and Bones
In the early 1980s, Sutton used a combination of public-domain information on Skull and Bones (such as Yale yearbooks) and previously unreleased documents sent to him by Charlotte Thomson Iserbyt whose father was a Skull and Bones member to write "America's Secret Establishment: An Introduction to the Order of Skull and Bones", which, according to Sutton, was his most important work.