The Congress had lost political focus after his elevation as the President and some party members believed that had he become the prime minister in 2004, the 2014 Lok Sabha poll debacle could have been averted, Pranab Mukherjee wrote in his memoir.
Mukherjee completed the book "The Presidential Years" before his death. It will be published by Rupa in January.
The former president died on August 31 at the age of 84, following COVID-19 complications.
His observations come at a time of intense internal turmoil in the Congress.
The publishers issued a statement announcing the book.
"Some members of the Congress have theorised that, had I become the PM in 2004, the party might have averted the 2014 Lok Sabha drubbing. Though I don't subscribe to this view, I do believe that the party's leadership lost political focus after my elevation as president. While Sonia Gandhi was unable to handle the affairs of the party, Dr (Manmohan) Singh's prolonged absence from the House put an end to any personal contact with other MPs," Mukherjee is quoted as saying in his book.
"I believe that the moral authority to govern vests with the PM. The overall state of the nation is reflective of the functioning of the PM and his administration. While Dr Singh was preoccupied with saving the coalition, which took a toll on governance, (Narendra) Modi seemed to have employed a rather autocratic style of governance during his first term, as seen by the bitter relationship among the government, the legislature and the judiciary.
"Only time will tell if there is a better understanding on such matters in the second term of this government," Mukherjee said in the book, according to the statement by Rupa.
Mukherjee was the 13th President of India after having spent five decades in politics.
The book gives a rare glimpse of his fascinating journey from a remote village in Bengal to the Rashtrapati Bhavan.
"This is a deeply personal account of the manner in which one of the country's most respected, veteran politicians reshaped the functioning of Rashtrapati Bhavan and responded to tumultuous events as the country's first citizen, leaving behind a legacy that will be hard to match," the statement said.
In this first-person account, Pranab da, as he is affectionately called, recollects the challenges he faced in his years as President - the difficult decisions he had to make and the tightrope walk he had to undertake to ensure that both constitutional propriety and his opinion were taken into consideration, it further said.
The book also reveals a minor diplomatic issue that arose during the visit of US President Barack Obama in 2015 when the US Secret Service insisted that their president travel in a specially armoured vehicle that had been brought along from the US, and not in the car designated for use by the Indian head of state.
"They wanted me to travel in the same armoured car along with Obama. I politely but ¬firmly refused to do so, and requested the MEA to inform the US authorities that when the US president travels with the Indian president in India, he
would have to trust our security arrangements. It cannot be the other way around," Mukherjee wrote in the no-holds-barred account.
