Ms Rice is herself criticised in the book
US Secretary of State Condoleezza Rice has rejected claims from a former White House press aide that President George W Bush misled the US over the Iraq war.
Ms Rice refused to comment directly on the book by Scott McClellan but said Mr Bush had been "very clear" about the reasons for going to war.
She said the US had not been alone in believing Iraq was a serious threat.
Mr McClellan has accused Mr Bush of a lack of openness and having relied on a "propaganda campaign" to sell the war.
His 341-page memoir, What Happened: Inside the Bush White House and Washington's Culture of Deception, is to be published on Monday.
Extracts quoted by US media give an often scathing view of both the president and his highest-ranking aides.
From July 2003 to his resignation in April 2006, Mr McClellan was a loyal defender of the Bush administration. He had previously worked for Mr Bush when he was Texas governor.
The book has provoked strong reactions from supporters of the Bush administration.
Ms Rice, speaking in Sweden at an international conference on Iraq, told reporters: "I am not going to comment on a book that I haven't read.
"But what I will say is that the concern about weapons of mass destruction was the fundamental reason [for going to war]."
In the memoir, Mr McClellan depicts Ms Rice as being "more interested in figuring out where the president stood and carrying out his wishes" than helping him understand the consequences of war.
He says she "was somehow able to keep her hands clean" but predicts that "history will likely judge her harshly".
Mr Bush has yet to comment on the book himself, but White House spokeswoman Dana Perino issued a statement on Wednesday dismissing Mr McClellan as "disgruntled".
She added: "For those of us who fully supported him, before, during and after he was press secretary, we are puzzled. It is sad - this is not the Scott we knew."
Former senior Bush adviser Karl Rove, now a political commentator for Fox News, attacked Mr McClellan for not speaking up sooner if he had concerns about White House policies.
Former White House counsellor Dan Bartlett was also critical of his one-time colleague.
"If he thinks he's going to ingratiate himself to his critics, he's sorely mistaken, and unfortunately, the only friends he had, he just lost," Mr Bartlett said, quoted by Reuters news agency.
In his memoir, Mr McClellan says that Mr Bush was not "open and forthright" on Iraq and accuses him of "rushing to war with inadequate planning and preparation for its aftermath".
Mr McClellan criticises Mr Bush's handling of Iraq and Hurricane Katrina
Mr McClellan stops short of saying Mr Bush lied about the reasons for going to war in Iraq - a war the former press aide judges "not necessary" and a "serious strategic blunder".
However, the way the Bush administration managed the Iraq issue "almost guaranteed that the use of force would become the only feasible option", he says.
Mr McClellan describes White House staff as spending much of the first week after Hurricane Katrina in 2005 "in a state of denial".
He also accuses former senior Bush strategist Karl Rove and Lewis "Scooter" Libby, Vice-President Dick Cheney's former chief of staff, of misleading him about a CIA leak case involving White House staff.