The CIA admits that the volume contains only a small amount of still-classified information. It argues, however, that it should be covered by the “deliberative process privilege” that makes it exempt from release under the Freedom of Information Act. The argument is that, for some unclear reason, release of this volume, unlike the release of the first four volumes, would threaten the process by which the CIA’s histories are written. Supposedly candid histories will not be written if the writers know that, decades later, their work will become public.

This unpersuasive worry — an excuse for the selective censorship of perhaps embarrassing scholarship — is surely more flimsy than the public’s solid interest in information. And the government’s interest.

In his 1998 book “Secrecy: The American Experience,” Sen. Daniel Patrick Moynihan argued that secrecy makes government stupid by keeping secrets from itself. Information is property, and government agencies hoard it. For example, in the 1940s, U.S. military code breakers read 2,900 communications between Moscow and its agents in America. So, while the nation was torn by bitter disagreements about whether Alger Hiss and the Rosenbergs committed espionage, the military knew they had. But it kept the proof from other parts of the government, including President Harry Truman.