In his autobiography, Mr Bush focuses on 14 major decisions of his life and presidency Former US President George W Bush still has “a sickening feeling” about the failure to find weapons of mass destruction in Iraq, US media report.
The revelation comes in his memoir, “Decision Points”, to be published next week.
He also reveals that he temporarily considered replacing Vice President Dick Cheney, calling him the “Darth Vader of the administration”.
But he has no comment on his successor in the White House, Barack Obama.
In the autobiography, Mr Bush defends his decision to invade Iraq, according to advanced copies of the book.
He argues that both America and the Iraqis are better off without former Iraqi leader Saddam Hussein, whom he calls a “homicidal dictator”.
But Mr Bush admits that he was shocked when no weapons of mass destruction were found in Iraq.
“No one was more shocked and angry than I was when we didn’t find the weapons,” he writes. “I had a sickening feeling every time I thought about it. I still do.”
The former president also describes how he considered an offer by Vice President Dick Cheney to step down in 2003 so that Mr Bush could pick a different running mate for the 2004 election campaign.
“He had become a lightning rod for criticism from the media and the left,” Mr Bush writes.
“He was seen as dark and heartless.”
But Mr Bush writes that he decided to stick with Mr Cheney because he had chosen him “to do the job” and “that was exactly what he had done”.
According to media who obtained the autobiography, Mr Bush focuses on anecdotes and details of 14 major events of his life and presidency, including the decision to stop drinking and his decisions following the attacks of 11 September 2001.
He admits he made mistakes when responding to Hurricane Katrina in 2005 and describes how he felt “like the captain of a sinking ship” when the economic crisis escalated towards the end of his presidency in 2008.
But he adds: “The financial crisis should not become an excuse to raise taxes.”
This article is from the BBC News website. © British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.