The book quotes NPR reporter Nina Totenberg, who covered the Clinton administration's most inglorious moment when Republicans got Clinton impeached for lying about having sex with Monica Lewinsky, the New York Daily News reported Friday.
Clinton had the "mentality of an 18-year-old" when it came to sex, Totenberg is quoted as saying.
That assessment appears in "A Complicated Man: The Life of Bill Clinton as Told by Those Who Know Him" by Michael Takiff.
Totenberg says she believes it was Clinton's inability to face his wife Hillary Clinton that led him to make the fateful lie.
Clinton aides like Paul Begala said they believed the president when he went on television and denied having sex with Lewinsky.
When the truth was revealed, Republicans were frustrated by the lack of public outrage, Takiff writes.
They thought the Clintons were "wizards who had somehow enchanted America out of its moral moorings," Rep. Barney Frank, D-Mass., said.
To this day, Republicans say, Clinton's behavior rankles.
"I never could bring myself to believe that in the case of Bill Clinton I was dealing with a serious adult," said former Texas Rep. Dick Armey.