He also used the occasion to attack his former Media Adviser Sanjaya Baru, saying he too had tried to market his book by making certain claims.
"This is their way of trying to market their product," the former Prime Minister said here.
He was responding when asked to react to certain comments made by his former colleague Natwar Singh about Sonia Gandhi with regard to her refusal to take up Prime Ministership in 2004 and other issues.
Asked whether he thought Baru also indulged in the same marketing tactic by making certain claims in his book 'The Accidental Prime Minister', Manmohan Singh said, "Yes."
Queried whether he thought it was fair for insiders to reveal certain details, the former PM shot back, "What revelations"
While saying that he had not seen Natwar Singh's autobiographical book 'One Life is Not Enough', he said, "Private conversation should not be made public for capital gains."
Natwar Singh, like Baru, has also claimed that PMO files were sent to Gandhi for approval.
When Manmohan Singh's attention was drawn to this, he said, "I had contradicted it then, I repeat that this is not true."