This piece was originally published in The Atlantic.

In 1963, Philip L. Graham, then the publisher of The Washington Post, gave a speech in which he delivered the memorable characterization of journalism as “a first rough draft of a history that will never be completed about a world we can never really understand.” That is still true today. But journalism’s “rough draft” has been increasingly joined over the decades by the memoirs of leading government figures whose tenure in office invariably leads to books that offer their perspective intended to frame the historical measure of their role.

There have always been memoirs of those who held high rank. But in today’s rhythm, the books appear as soon as possible after the official’s departure, while the events described are still of some widespread interest or dispute. The fate of most of these memoirs is short-term notoriety—plus a substantial payout to the author—and a chance to shape the long-term appraisal of their actions. What Graham said of journalism is also the case with hastily written, self-serving memoirs: “Much of it is, of course, pure chaff …. But no one has been able to produce wheat without chaff.”

Now, former Defense Secretary Robert Gates has taken the genre a substantial step forward by releasing a highly critical memoir while an administration he served still has three years left. The book has been justifiably praised by some for its depth and quality and vilified by others for its timing. In more than four years at the Pentagon, serving two presidents from opposing parties and overseeing two costly and unresolved wars, Gates earned a reputation for integrity and his ability to handle the intense policy and bureaucratic conflicts that bedevil every administration. When Gates’s book, Duty: Memoirs of a Secretary at War, landed on media desks in the first days of January (a week before it went on sale) it was an immediate sensation. Its gimlet-eyed portrait of prominent figures in Washington’s power elite at the White House, Congress, and the Pentagon—including many still at the helm—made it a natural hit.

In this era of Twitter reviews and cable news, every Gates critique could be rendered a newsmaking tidbit before a single copy had actually reached readers. Many of his colleagues in George W. Bush’s administration have already have had their say, including Vice President Cheney, Secretary of State Condoleezza Rice, and Defense Secretary Donald Rumsfeld, among others. Their books sold reasonably well but are largely forgotten. The Bush team gets its full share of Gates’ criticism for its succession of mistakes and misrepresentations in Iraq, Afghanistan, and Iran, but because these assessments are retrospective, they have been less controversial. In addition, nstead of eviscerating Rumsfeld at length for the debacle in Iraq, Gates writes only that he was “stunned by what I saw as amazing bungling after the initial military success” when he took over the Pentagon in December 2006. He also writes that Bush told him before leaving office that he wished he had replaced Rumsfeld two years earlier.

What makes Duty such a significant departure in the arena of memoirs is that his account of President Obama, Vice President Biden, and Senate Majority Leader Harry Reid, to name only a few, is that they are still defining the national agenda. Whatever differences they may have had with Gates when they worked together, it is unlikely they were prepared for his dour assessment of their shortcomings, even when ostensibly offset with positive asides. Over 640 pages, what comes through most clearly—and what may well be its lasting legacy—is how much frustration, anger, and even despair Gates increasingly felt despite his apparently stolid equanimity. In fact, the only real heroes of the book are the servicemen and women Gates encountered in the field and in hospitals. His countless nights of writing letters to the families of the fallen in what he plainly considers wars that that would never end in true victory, have left an indelible bruise on his soul. Gates told the Associated Press that he plans to give of most of his royalties to charities working with wounded soldiers.

Duty has been number one on The New York Times bestseller list for four weeks. There have been seven printings and about 375,000 copies already shipped, and e-book sales that are about to surpass 20,000. Undaunted by an accident on the eve of his scheduled promotional tour that had him in a unwieldy neck brace, Gates, at 70, has been unapologetic about shattering the convention of when it is suitable to be so forthright with criticism. In reflections about wars, especially given his views about how tragically they have evolved and why, Gates told CBS’s Rita Braver, “I didn’t think waiting until 2017 to weigh in on these issues and in a comprehensive and thoughtful way made any sense …. People gave me a lot of credit when I was in office of being blunt and candid about things. I could hardly be any less in writing a book.”

While Duty may be “a first rough draft of history,” it is a book that historians should take seriously as they try to decipher this tumultuous period. Robert Gates believes that speaking truth to power, as he sees it, is inescapably the duty that the title of his book is meant to convey.