Disgraced Politburo member Chen Xitong was reluctant to talk about the past for fear of political repercussions until scholar Yao Jianfu mentioned a conversation he had with purged leader Zhao Ziyang.
Yao, 80, said the interviews he had with Chen happened by chance and they had both worried that publishing the book could land them in trouble. But Yao, a former central government adviser, said he eventually decided to go ahead because he felt obliged to tell the public the true story.
'We are both in our 80s,' he said. 'We have never thought to overthrow the party or the government throughout our lives. What we want to do is simply to restore the truth and set the record straight. I think our current leaders are wise. A harmonious society should tolerate that.'
Yao said he was asked by a writer friend to deliver a book to Chen last year. The writer published a biography in which he recalled how Chen helped him during difficult times and asked Yao to take a copy to Chen.
Yao said Chen was at first reluctant to bring up the past until Yao mentioned a conversation in March 2004 with late Communist Party general secretary Zhao (pictured), who was purged after the 1989 crackdown on pro-democracy protesters in Beijing's Tiananmen Square.
Yao asked Zhao if Chen, Beijing's mayor at the time, and Li Ximing, the capital's then party secretary, had deceived late paramount leader Deng Xiaoping into making a wrong decision to send the People's Liberation Army into the square. Zhao said he did not believe that because 'Deng wouldn't be Deng if he could be easily tricked'.
'After hearing this, Chen clapped my knee and said, 'I absolutely agree with comrade Zhao Ziyang',' Yao said. 'To say that Chen Xitong tricked Deng Xiaoping is an insult to Deng's intelligence.'
Yao said Chen mainly wanted to set two records straight - his role in the Tiananmen crackdown and his rejection of the corruption case that led to his jailing in 1998.
Yao said Chen was physically ill but in high spirits.
'He never signed the confession letter and never acknowledged the corruption charges,' Yao said. 'He even refused to sign the medical parole letter because it mentioned his corruption charges.'
Chen was admitted to the Xiaotangshan hospital in 2004 but was only granted medical parole in 2006, after serving eight years of a 16-year sentence.
'He is spiritually free,' Yao said. 'He can travel freely within Beijing city. He goes to parks regularly and has many friends visiting.'
Chen is one of only three Politburo members brought down by corruption charges since the end of the Cultural Revolution. Both he and Chen Liangyu - the former Shanghai party secretary, were jailed. Former Chongqing party secretary Bo Xilai, whose scandal could prove to be far bigger, is still waiting to learn his fate.
Chen Xitong is proud of the fact that he never gave in.
'I was never handcuffed and never signed any confession letter,' Chen says in Yao's book, Conversations with Chen Xitong, published by Hong Kong's New Century Media.
'I saw on television how they treated Chen Liangyu. He was handcuffed and he signed the confession letter.'
Publisher Bao Pu said Chen Xitong's corruption case paled in comparison with those of Chen Liangyu and Bo Xilai.
'Actually, by today's standards in China, he probably could be considered a 'clean official',' Bao said. 'He is just a political pawn.'