This study makes extensive use of information drawn from internal, classified CIA files— from the records of the directors of central intelligence and of the staffs that assisted them in their role as leaders of the US Intelligence Community; from interviews conducted as part of CIA’s oral history program; from organizational histories and biographies of directors of central intelligence; and from Studies in Intelligence, a journal published by CIA since 1955. With some exceptions, these sources are not individually cited in the footnotes.

These internal, classified resources supplement openly available material, such as declassified official histories (Troy, Darling, Montague, and Jackson) covering William Donovan and the first five DCIs, as well as a number of memoirs, biographies, books, and commission studies devoted to intelligence, all of which are listed in the bibliography. The bibliography also lists the interviews conducted by the author for this study.

The author must confess to being a source, and necessarily one biased by his background. He worked at CIA from 1972 until 1999, starting out in the Office of National Estimates, spending most of the 1970s and 1980s as an analyst of Soviet affairs in the intelligence directorate, and serving in the 1990s as a senior manager in several offices and staffs in other directorates and in the Office of the Director of Central Intelligence, including the Community Management Staff. Although this career included service under 11 of the 19 DCIs who served from 1946 to 2005, he only briefly met Richard Helms and William Colby and—apart from interviews—knew personally only the DCIs of the 1990s, working most closely with Robert Gates and R. James Woolsey.