he commission that investigated the events of 9/11 has been highly praised and sharply criticized, but one aspect of its task has virtually escaped notice: its responsibility to leave behind a complete, lasting, and easily accessible public record of its investigation. For all the good work that the panel did, some of its decisions have eroded the public's right and ability to understand what happened on September 11, 2001.

Raising this issue may seem a quibble, given that the 9/11 Report is one of the best-selling government documents of all time. But history shows that reports of comparable magnitude, and the first reaction to these reports, have been inexorably colored by exigencies of the day. Time has a way of changing initial public opinion. Indeed, one media flap (like the still-unresolved questions about the Pentagon's Able Danger data-mining program), can destroy a commission's carefully cultivated reputation in a matter of days. Consequently, the true measure of such investigations is not just their final reports or recommendations. These panels are ultimately judged on the totality of information they bring into the public realm; what they make knowable, in other words.

Traditionally, this deeper purpose has meant that final reports of important commissions have been supplemented by publication of the public and private hearings, staff reports and the actual documents used to compile the findings. Take a look at the shelf space occupied by some major probes since 1945: these include the 1946 congressional inquiry into the Pearl Harbor attack (40 volumes); the 1964 Warren Commission investigation of President Kennedy's assassination (27); and the 1975-76 Church Committee investigation of the intelligence agencies (15).

By contrast, the 9/11 Commission climaxed in the publication of a single, 567-page volume—without an index. The relative poverty of this effort at the culmination of a twenty-month, $14 million investigation reflects a downward trend in the government's obligation to disseminate information to the public. This policy began in the 1980s, when, for ideological reasons, the Reagan administration reduced the number and availability of government publications. The worrisome tendency has accelerated with the advent of the Internet.

THE PEOPLE'S PUBLISHER—Much of this story concerns the U.S. Government Printing Office (GPO), whose lineage as the principal agent for delivering public information goes back to 1860. "Keeping America Informed" is the GPO's motto, and over the years its imprimatur has acquired symbolic and legal significance. The sober look of a GPO volume conveys weight and authenticity. The symbolism is embedded in the law as well. The U.S. Code still states that "all [federal] printing . . . shall be done at the Government Printing Office."

The 9/11 Commission's first departure from customary practice was its decision not to use the GPO. On May 19, 2004, the commission announced that W.W. Norton, a private New York publisher, would publish the "authorized edition" of its final report. According to the commission's press release, Norton was selected based on the criteria of "affordability, accuracy, availability, and longevity." There was no mention of a role for the GPO, which had long done a sterling job by these standards.

Nothing in the law stops private publishers from also printing government documents, as such documents are not covered by a copyright. Sometimes several different publishers will put out an edition of the same report. About 35,000 commercial copies of the Warren Report were in bookstores one day after the GPO published it in 1964, and there was every reason to believe the same phenomenon would occur with the 9/11 Report. Certainly, never before had a publisher other than the GPO been the first to publish the report of a comparable government investigation.