The Aug. 3 call to "put an end to all terrorist activities now and forever" was made in the form of an open letter to the shadowy figure who has killed three in a 17-year bombing spree. Mr. Guccione repeated an earlier offer of an uncensored monthly column in Penthouse "indefinitely into the future" following publication of the manifesto.
The $60,000 ad ran a day after both the Times and The Washington Post published 3,000-word excerpts from the Unabomber's 35,000-word treatise that railed against science and the increasingly technological modern society.
The Unabomber sent the manifesto to all three publications in late June, with the demand one of them publish it in order to avoid more killing. The bomber-imposed deadline for the papers is late September, while Mr. Guccione has an additional three months after that to publish.
The two big dailies are still anguishing over a decision, pondering whether the potential to save lives outweighs the danger of giving in to terrorism.
"The tough decision of whether we publish the entire document is still ahead," said New York Times Publisher Arthur Sulzberger Jr. An added stumbling block is the Unabomber's demand for three annual follow-ups to be printed over three years, a provision that Mr. Sulzberger has called "especially troubling.
"There is no easy way to open negotiations with this person, and for the moment we're stymied," he said last week.
Mr. Guccione's stance to use the pages of one of the newspapers for his own public negotiations is seen by some as a grandstanding publicity stunt by a person who has proven a master of the art over the years.
Mr. Guccione defended his move, claiming the excerpts that appeared in the papers last week are unlikely to fulfill the Unabomber's demand to publish. He also told the Unabomber he understands the daily papers' reluctance to avoid agreeing to publish additional essays.
"A commitment to publish something, sight unseen, well into the future is unlikely to win favor at either the Times or the Post," Mr. Guccione said in his letter, "nor would anyone in our industry blame them."
If the papers don't publish, the Unabomber said in his communications in late June, the copyright passes to Penthouse. Since he deemed the monthly men's magazine to be a "less respectable" publication than the two big dailies, the Unabomber said he reserved the right to kill one more person if the essay ended up in Penthouse.
"I cannot accept that," Mr. Guccione said in the open letter "nor can I accept your characterization that Penthouse is strictly an entertainment magazine and therefore any serious non-sex related editorial is read as `entertainment."'
He also took the Unabomber to task for "changing the rules" and adding the follow-up provision in his late June letter after failing to mention it in an earlier letter to the Times on April 24, when he said he would accept publication in a major national publication like Time, Newsweek or the Times. Neither Time nor Newsweek has ever been contacted, said executives at the two magazines.
Mr. Guccione, in the letter to the Unabomber, said he disagreed with the bomber's portrayal as a serial killer.
The FBI now says it believes the Unabomber was based around campus communities in Chicago, Salt Lake City, and Sacramento, Calif., and/or the San Francisco area.
Last week, copies of the manuscript were sent to dozens of college professors who specialized in the study of the history of science. The FBI said it hopes that the professors will recognize a former student or colleague in the writings.