The National Security Agency, headquarters for the government's eavesdroppers and code breakers, has been located at Fort Meade, Md., for half a century. Its nickname, the Fort, has been familiar for decades to neighbors and government workers alike. Yet that nickname is one of hundreds of supposed secrets Pentagon reviewers blacked out in the new, censored edition of an intelligence officer's Afghan war memoir. The Defense Department is buying and destroying the entire uncensored first printing of Operation Dark Heart, by Anthony Shaffer, a lieutenant colonel in the Army Reserve and former Defense Intelligence Agency officer, in the name of protecting national security. Another supposed secret removed from the second printing: the location of the Central Intelligence Agency's training facility - Camp Peary, Va., a fact discoverable from Wikipedia. And the name and abbreviation of the Iranian Revolutionary Guard Corps, routinely mentioned in news articles. And the fact that Sigint means "signals intelligence." Not only did the Pentagon black out Colonel Shaffer's cover name in Afghanistan, Chris Stryker, it deleted the source of his pseudonym: the name of John Wayne's character in the 1949 movie "The Sands of Iwo Jima." The redactions offer a rare glimpse behind the bureaucratic veil that cloaks information the government considers too important for public airing.