Clemens said that any evidence, such as syringes provided by McNamee, his former trainer, that allegedly link him to the use of steroids or human growth hormone cannot exist.
"Impossible, because he's never given me any," Clemens said. "He's never given me HGH or any performance-enhancing drugs."
According to McNamee's attorney, Clemens' comments were tantamount to dropping a gauntlet at the feet of federal investigators reportedly looking into whether he perjured himself during his February 2008 appearance in front of a House committee.
In several interviews following Clemens' appearance, including one on ESPN and one with The Associated Press, attorney Richard Emery likened Clemens' defiance to "poking a stick in the federal government's eye."
"The only thing new is [Clemens'] tactic of actually speaking publicly, which I think is going to be like poking a stick in the federal government's eye and Congress' eye because he is basically saying he didn't lie to Congress when it is perfectly obvious that he did," Emery said. "I think it is going to speed up and energize the prosecution."
"American Icon: The Fall of Roger Clemens and the Rise of Steroids in America's Pastime" was written by four reporters from the New York Daily News who, according to a story published Monday by that newspaper, concluded that Clemens had lied last year in a deposition and at the hearing.
"It's piling on," Clemens said. "It's hurtful at times, but I'm moving on.
"All I can do is speak the truth and from the heart. I know what your polls say, [but] I get great responses in every city I go to. ... When you've got someone out there crawling up your back to make a buck -- and that's what it is -- how do you defend a negative? The garbage that's in this book, I've got an opportunity to [talk about] that today."
According to New Jersey-based sports attorney Jerrold Colton, it might not be the best strategy for Clemens to be talking at all.
"If I'm representing the guy, I don't want him talking, because it's even though it's not an under-oath statement, it's the old 'everything you say can and will be used against you' scenario," Colton told MLB.com. "He's already got a full body of statements, and he's just not helping himself."
Colton added that Clemens might be continuing to deny his use of steroids to avoid incriminating himself by contradicting earlier statements, but that he's probably talking for one of two reasons.
"Either he's telling the truth or he's just so defiant and so adamant in his denials that he's backed himself into that corner," Colton said. "You almost get the feeling, whether it's true or not, that he believes what he's saying.
"And there's such an arrogance to it, whether true or not, and that's probably Roger's personality. That's what made him such a tremendous competitor and pitcher and it doesn't change when you're in this legal kind of realm.
"The bottom line is that I would have advised him to lay low from the start. I don't see any way he could benefit himself from talking, especially under the specter of criminal prosecution. I know he's a smart guy and he's doing this with the advice of attorneys, but it's still hard to believe."
The Daily News said that its reporters -- Teri Thompson, Nathaniel Vinton, Christian Red and Michael O'Keeffe -- came to their conclusion after interviewing scores of sources, including Major League Baseball players and executives, Players Association officials, political leaders, law-enforcement agents, steroid suppliers, trainers, doctors and gym rats.
The reporters also reviewed thousands of pages of documents -- including court records, Congressional depositions, medical files and the Mitchell Report -- while preparing the book.
One of the collaborators, Vinton, said, "Our book is really backed up by a lot of documentation and interviews with key players. It's not false; we really researched this carefully ... and take it very seriously."
Clemens, a 354-game winner who last pitched in 2007 for the Yankees, sued McNamee for defamation. A judge dismissed most of that suit, but it remains active. Clemens said that he has not been summoned by Congress.
"The legal proceedings are still going on," Clemens said. "Like I said, I'm trying to stay positive about it. I know I'm a public figure, but I'm getting out there and doing the things I normally do. I hear people saying that you're not doing this or doing that, but I've been doing what I normally do," instructing high school and college players as well as taking part in charity events such as dinners and golf tournaments.
Clemens offered generic answers to questions from hosts Mike Greenberg and Mike Golic about Manny Ramirez and Alex Rodriguez, who this year have been connected to steroid use, recently in the case or Ramirez and dating back, for Rodriguez, to his seasons with the Rangers. Ramirez was suspended last week for 50 games and Rodriguez admitted to using steroids from 2001-03 after a report revealed that he had tested positive in survey testing in 2003.
He said that he didn't know the "exact details" of Ramirez's suspension, and said of Rodriguez, a teammate in 2007, "I just wish him the best."
Clemens repeatedly said that he talks to young people about the dangers of steroid use, and restated his claim that former teammate Andy Pettitte "misremembers" a conversation the left-hander testified to that he and Clemens discussed steroid use.
Gene Grabowski, senior vice president of Levick Strategic Communications, which has been hired by Clemens, appeared on the show an hour earlier and explained why his client had decided to begin speaking publicly again.
"He realizes that he has to get out there, defend himself, and in the end we'll find out that he's been falsely accused," Grabowski said. "It's no coincidence. This book ... there's nothing new in it. It's a patchwork job, a narrative [of newspaper stories] woven together in a more enticing way. It's filled with a lot of the lies that were repeated before.
"Roger feels a need to get out there and tell his side of the story before it gets out of hand and people's opinions are cemented."