For more than 30 years, the Family Jewels have clouded the C.I.A.’s reputation, even though most of their contents have long been known from official reports and ad hoc disclosures. William Colby — who oversaw the compilation of the Jewels while serving as the agency’s operations chief and director-designate — is the source of some durable misconceptions about them. In his memoir, Honorable Men (p. 340), Colby says that the Jewels consist of “693 pages of possible violations of, or at least questionable activities in regard to, the C.I.A.’s legislative charter”; that among the contents are “bizarre and tragic cases wherein the Agency experimented with mind-control drugs”; and that accompanying them was “a separate and even more secret annex” that “summarized a 1967 survey of C.I.A.’s involvement in assassination attempts or plans against Castro, Lumumba and Trujillo.”

These misstatements were repeated at least in part in several widely read works, including Thomas Powers’s The Man Who Kept the Secrets, John Ranelagh’s The Agency, G.J.A. O’Toole’s Encyclopedia of American Intelligence and Espionage, and Norman Polmar and Thomas Allen’s Spy Book. Less informed observers also have suggested that the Jewels include details about political and paramilitary covert actions and definitive proof that the C.I.A.’s controversial counterintelligence chief, James Angleton, was the mastermind behind the domestic spying program called MHCHAOS.

The release of the Jewels should end much of the mythology about them. For starters, the compendium is not a 693-page catalogue of crime and immorality. Repetitive reports, duplicate documents, blank pages, file dividers, cover sheets, distribution lists and news clippings comprise approximately 30 percent of the total. Among the remaining 500 or so pages of substance, except for an account of the use of Mafioso Johnny Roselli in a plot to kill Castro (12-16) — of note is that the director of central intelligence at the time, Allen Dulles, approved it — there are only passing references to already disclosed assassination plots and drug-testing programs and next to nothing of importance about purely foreign operations.

That may disappoint some expectant readers but should not be surprising because the whole point of an order by James Schlesinger, a later director of central intelligence, that produced the Jewels was to get information about activities that possibly violated the C.I.A.’s charter. Consequently, the collection is nearly all about activities involving American citizens or occurring inside the United States — most of the latter, as an Agency officer noted, “completely innocent, although subject to misconstrual” in the political atmosphere of 1973 (36) — and includes much about agency contact with the White House “Plumbers,” the Watergate break-in perpetrators, and now-obscure characters such as the fugitive financier Robert Vesco. The hypersensitivity about anything that could be interpreted as having domestic political implications — or perhaps simply the bureaucratic instinct for self-protection — may explain the inclusion of the lengthy set of mundane documents about a small C.I.A. expenditure for postal services on behalf of the White House (83-104), and a memo about the Office of Logistics disposing of the National Security Council’s classified trash (324)....