FORTUNE — Glenn Hubbard is calling Tim Geithner a liar.

One bit of gossip bubbling up from the former Treasury Secretary’s new book Stress Test, which was released Monday, is the idea that Glenn Hubbard, economic advisor to Mitt Romney’s presidential campaign, privately told Geithner that Republicans would have to raise taxes if Romney won the election.

Hubbard told Politico that the story was a lie. CNBC reported Monday that a representative of Geithner had issued a statement standing by the story, saying the former Treasury Secretary’s memory on the exchange between the two men is “crystal clear.”

Hubbard is currently dean of Columbia Business School, and he was chairman of the Council of Economic Advisers in the George W. Bush administration.

In a review of Stress Test in the New York Times, critic Michiko Kakutani notes that the tome “does not provide any big new revelations, nor does it shed new light on the inside workings of the Obama White House.” Instead, she writes, it makes an attempt to explain the reasoning behind the decisions made by Obama, Geithner, and others in dealing with the financial crisis.

To celebrate the Monday launch, Geithner made an appearance on CNBC’s Squawk Box. Here are a few choice quotes from his appearance:

On the state of the American financial system:The country still has a lot of challenges. Americans as a whole feel less confident still that they are going to be able to build a better life for their children.”

On the idea that he was too close to Wall Street:I didn’t think [Wall Street] was a terrifically noble or ethical profession … nor did I think it was a profession that had a disproportionate share of people who are ethically challenged.”

On criticism from Elizabeth Warren in her recent book: “We did reforms to the systems; much stronger consumer protection.”