Rittenberg's life reads like several lived simultaneously. Born in 1921, he was a student communist in America's deep south and became a fluent Putonghua speaker, thanks to specialist army language training. Having secured his discharge he joined the United Nations Relief and Rehabilitation Agency in Shanghai in 1946. From there he was co-opted to be an interpreter for the truce teams set up by US special envoy General George Marshall to conciliate all three sides - US Army, nationalists and communists - in the Chinese civil war.

In that capacity, he met Chinese Communist Party leader Zhou Enlai, who invited him to the communist 'capital-in-the-caves' at Yanan and introduced him to Mao Zedong. Determined to join the revolutionary struggle, Zhou's protege was soon translating party propaganda into English for what became Radio Beijing. He continued this work, when not in jail, during his 35-odd years in China.

Rittenberg joined the Communist Party, but four years later his personal links with the leaders failed to save him from jail on false charges of being a US spy. Even after six years in solitary confinement, his faith in the party never faltered.

Then, one day in 1955, he was told it was all a mistake. He was released, with apologies from Mao and Zhou. Instead of catching the first flight home, he stayed in China, regaining both his party membership and his old job at Radio Beijing. He was determined to show that he was a true and loyal communist.

In the mid-1960s, the political winds changed and he was again denounced as an American spy and jailed in a tiny isolation cell, this time for 10 years. He was astounded. The Communist Party, which called itself 'great, glorious and correct', had now wrongly imprisoned him twice. 'How can a man be so smart and so dumb at the same time?' wondered The Washington Post.

Speaking recently to the South China Morning Post, Rittenberg said he would change little if he lived his time again. He has some regrets, such as 'the times when I got involved in internal Chinese politics and stood with one group of Chinese against another group of Chinese'.

He remembers one period, in particular. 'In the Cultural Revolution in the beginning, [I] took up the cudgels along with the crowd against this one and that one, and it was really quite wrong. It was particularly wrong for me, being an American citizen and injecting myself into it, especially when, in the Cultural Revolution, I could criticise anyone but they couldn't publicly criticise me, because I was a foreigner. I very much regret things of that sort.'

This would seem to have been Rittenberg as 'The Foreigner Who Did Not See He Was Foreign'. While he was imprisoned the second time during the Cultural Revolution, his wife, Yulin, and four children - the youngest, Sidney, was only two - were also locked up. 'They were first incarcerated with their mother for eight months, under severe house arrest in a small hotel room that was being used as a Cultural Revolution prison,' he said.

Then Yulin was sent to a hard-labour camp, where young Sidney joined her while his siblings stayed with their grandparents. 'He helped her by tying a little rope to the front of her wheelbarrow, heavy with bricks, to tug at it when she had to push it up inclines.'

Rittenberg emerged from prison after 10 years to find socialism had failed, but still he remained in China. The party apologised once again, this time in writing. 'It said, 'He was done wrong; he was framed; investigations revealed 30 years of devotion to China',' Rittenberg said, more amused than triumphant.

Finally, in 1980, the Rittenbergs went to live near Seattle, in the US.

To Rittenberg, this decision was simple. He patiently explained that his life's purpose had always been to build bridges between China and America, to harness one's vast population and poverty with the technology and resources of the other. 'When I got out the second time, I thought I could do more on the bridge from the US side,' he said.

He sounds sanguine, almost passive as he reflects on past events. Surely he resented being unjustly jailed for 16 years? It seems not. 'Prison really turned out to have been a rather good thing, if you were able to learn about yourself. All in all, it was an addition to my life,' he said.

Nevertheless, there is an inescapable irony in the fact he now makes his fortune cutting deals between US companies and his former comrades in China.

In spite of everything, he still speaks with awe and reverence of the great leaders. Zhou was something like chief of staff to Mao, he explained. 'He had the faculty, which tragically Mao completely lacked, of protecting himself from the corruption of power. He never changed from being the plebeian he started out being.'

Mao was a different matter. 'I just remember that great brain. He was a genius like no one I've ever met, a philosophical and analytical genius, a man of great broad vision.' But Rittenberg said he remembered the great harm Mao did too. 'I would say he was the great leader in history and a great criminal, both of those things.'

Mao's fatal flaw was a simple one. 'It was corruption of power. It totally changed him,' said Rittenberg. 'There was no system that would make him part of a collegial group, so when he went on the rampage there was no one who could stop him. In China, you don't have rule of law, you have rule of the man in charge.'

He learned of Zhou's death in March, 1976, in jail. Yulin told him afterwards that China had been convulsed with grief. 'Zhou was such a warm person that I felt a deep personal loss,' he said.

Mao's death followed that September. He heard thunderous funeral music and knew immediately. 'In my mind, then, he was the great matchless leader. The future of humanity required that he be there. I thought, 'Who will give guidance now?'.' After nine years in jail, he had little idea what had been going on. 'Yet I didn't shed a single tear,' he said.

So what did he make of Premier Wen Jiabao and President Hu Jintao? The early signs were good, he said. It seemed they were trying to tackle critical problems, such as the need to close the gap in living standards between the prosperous urban dwellers and the 850 million in rural poverty. He liked the way they had declared war on corruption, saying it was a matter of life and death for the Communist Party.

Ordinary people had been impressed by the new leaders, he said. People saw top leaders visiting contagious disease wards daily during the last Sars outbreak and having lunch with Peking University students without protective masks. 'I think people began to feel a flesh- and-blood connection with the leaders which they have not felt for a long time,' he said.

Rittenberg, a poetry lover, is an eternal optimist. Musing on China's future, he recited Tennyson's lines:

'Yet I doubt not through the ages one increasing purpose runs,

'And the thoughts of men will widen with the setting of the suns'