As former President George W. Bush works on his memoir, his detractors are doubting the candor of an unpopular leader famous for giving himself the highest of approval ratings.

Bush has signed with Crown Publishers for "Decision Points," a survey of fateful choices from running for president to invading Iraq. The book is scheduled for 2010, and while Bush said recently that "absolutely, yes," he would question some of his decisions, he added that he would make clear the difficulty of circumstances and the ease of hindsight.

So don't expect harsh self-appraisals about his response to Hurricane Katrina or the collapse of the economy or the failure to find weapons of mass destruction in Iraq. But don't be surprised, for no chief executive has written a book in order to say he failed.

"It's unfair to jump on Bush for not writing a self-flagellating memoir," says presidential historian David Greenberg, whose books include "Nixon's Shadow" and a biography of Calvin Coolidge. "It's a genre, a political genre, and it has different standards, needs to be read differently from other kinds of memoirs."

Memoirs are written for money, for revenge, for glory, for the first and perhaps last word. If we saw the world only through presidential eyes, the Great Depression would be Europe's fault, not Herbert Hoover's; liberals and other scoundrels were to blame for Richard Nixon's fall; and James Buchanan was a great man worthy of the president who succeeded him _ Abraham Lincoln.

The most disliked presidents were capable of the most prolonged defenses. Nixon wrote book after book after his resignation. Hoover needed three volumes, not only to absolve himself of the Depression, but to tear down the New Deal and its beloved, martyred creator, Franklin Roosevelt

A truly introspective work might have come from Lincoln, had he survived his second term. Instead, the toughest White House critic we have is John Quincy Adams _ like Bush, the son of a president _ although his recriminations were noted in his diary, not in public.