Ayers describes phone threats and hate e-mail he received during the campaign, and he bemoans Obama's guilt by association.
Obama had dismissed Ayers as "a guy who lives in my neighborhood" and "somebody who worked on education issues in Chicago that I know."
A campaign spokesman told The New York Times last month that Ayers and Obama hadn't spoken by phone or exchanged e-mail messages since Obama became a U.S. senator in January 2005. Obama himself denounced the "detestable acts" Ayers engaged in during the Vietnam era.
In the updated version of his 2001 book "Fugitive Days," Ayers calls into question one of the more incendiary quotes attributed to him during the campaign: "I'm nowadays often quoted as saying, 'I don't regret setting bombs. I wish we'd set more bombs. I don't think we did enough.'
"I never actually said that I 'set bombs,' nor that I wished there were 'more bombs.' ... I killed no one, and I harmed no one, and I didn't regret for a minute resisting the murderous assault on Viet Nam with every ounce of my being."
He was particularly disturbed by a newspaper headline published in 2001: "No regrets for a love of explosives."
"That's neither my narrative nor my sentiment," Ayers wrote, "but the idea was seized upon by the neocon media machine: I was an unrepentent and violent terrorist."
Ayers wrote the new afterword on July 4, "in the heat of the summer presidential campaign, with all its attendant bells and whistles and spin, all the diversion and dissembling that happens every four years when the big election carnival rolls into town."
Now a professor at the University of Illinois at Chicago and an expert on public school reform, Ayers was a member of the Weather Underground, a radical organization that claimed responsibility for a dozen bombings from 1970 to 1974.
He'll appear Friday on "Good Morning America" to promote the re-issue of his book this week. The Tribune obtained a copy of the updated material.
In it, Ayers -- who did not respond to requests for comment -- summarized his relationship with Obama: "[W]e had served together on the board of a foundation, knew one another as neighbors and family friends, held an initial fund-raiser at my house, where I'd made a small donation to his earliest political campaign."
Ayers lamented that his relationship with Obama became an issue.
"The more serious point is that Obama was asked once more to defend something that ought to be at the very heart of democracy: the importance of talking to many people in this complicated and wildly diverse society, of listening with the possibility of learning something new, of speaking with the possibility of persuading or influencing others. ... In a robust and sophisticated democracy, political leaders, indeed, all of us, would seek out ways to talk with many people who hold dissenting, even radical, ideas."
Obama was criticized by Sen. John McCain throughout the campaign for suggesting that, as president, he would sit down with the leaders of rogue nations like Iran and attempt to have substantive discussions.