Sidney Rittenberg: Chairman Mao's favourite American
As China's Communist Party marks its 90th birthday, one man has a unique perspective - an 89-year-old American ex-communist who spent 35 years in China and rubbed shoulders with Chairman Mao.
Sidney Rittenberg has lived a life usually seen only in Hollywood movies.
As a young man, he turned his back on the country of his birth, the United States, and threw in his lot with China's fledgling Communist Party.
He personally knew the revolutionary leader Mao Zedong, spent time in solitary confinement after being accused of spying and, disillusioned, finally returned to America following a second stint in prison.
But the 89-year-old has never lost his love for China and its people, and now returns regularly for work and to see old friends.
As the Chinese Communist Party celebrates its 90th anniversary, there can be few people still living who have seen its ups and downs from such close quarters.
Born in South Carolina into a prominent family, Sidney Rittenberg came to China with US forces in 1945, at the end of World War II.
His left-wing beliefs - and China's pitiful state at that time - naturally drew him towards Mao's communist party, based in the minor inland city of Yan'an.
"The normal state of existence for way over half of the people was hunger and the communists were the only group trying to get China out of that kind of poverty," he told the BBC while visiting the home he still keeps in Beijing.
At the time China was ruled by Chiang Kai-shek and his Nationalist Party. The victory of the communists was, for many, still an unlikely outcome.
In Yan'an, Mr Rittenberg worked for Xinhua, the news agency that still exists today, and regularly rubbed shoulders with the party's leaders.
He became a party member.
"If you were walking down a road and ran into Mao Zedong, Zhou Enlai or whoever, it was no big deal - it was normal," he said.
"You might stop and chat - anyone might stop and chat. You didn't feel a gulf."
But a gulf eventually did open up between him, a foreigner, and the Chinese revolutionaries he supported.
They blamed overseas powers, such as Britain and France, for many of China's problems and so a foreigner was always likely to be viewed with suspicion.
And so it turned out. Shortly after the communists took power in 1949, Mr Rittenberg was accused of being a spy and sent to prison. He spent time in solitary confinement, and was only released in 1955.
"I felt this terrible hurt. It's like you have a sweetheart that you've been in love with for years and it's been a wonderful relationship. All of a sudden, she appears in court and accuses you of rape," he said.
But Mr Rittenberg did not lose his faith in the Chinese communists and, when Chairman Mao launched his Cultural Revolution in 1966, the American was caught up in the hysteria of the times.
In the chaos, many were accused of political crimes at denunciation sessions that lasted for hours. The accused were often forced to wear dunce's caps and stand in painful positions.
Mr Rittenberg took part in these sessions. He said his participation was "inevitable".
"I was very enthusiastic about the prospect of building a world without classes, without war, without poverty - and it looked to me like this was what Mao was trying to do."
His verdict on Mao now? "He was a great historical leader and a great historical criminal - very few have reached this status in both of those aspects."
Eventually the Cultural Revolution turned on many of its fiercest advocates and, like many others, Mr Rittenberg was sent to prison again - as an "enemy" of the party.
Disenchanted with communism, on his release he decided to leave China for good with his Chinese wife and four children.
It was 1980 and he was about to start a new life as a consultant advising companies that wanted to do business in China, from a base across the Pacific Ocean, in Washington state.
At about the same time, China's Communist Party was also starting again. Under Mao's successor, Deng Xiaoping, it ditched many of the former chairman's ideas and principles.
In Mr Rittenberg's view, the new top leader saved the party, but changed it in such a way as to make it unrecognisable.
He said it might have to change again if it is to survive.
"We'll get to certain point where people will no longer be willing to have an advanced market economy and a backward political system," he said.
Sidney Rittenberg was born just a few weeks after the Chinese Communist Party held its first congress in Shanghai in 1921 and so, like the party, he will soon celebrate his 90th birthday.
And like the party, he is not thinking of retiring just yet - he is still too passionate about the country he adopted more than six decades ago.