There is a not inconsiderable history among the children of successful, prominent Jewish families of getting involved in leftwing politics. From the Marxes to the Milibands, it's a well-trodden path. Few have taken this tradition quite as far, however, as Sidney Rittenberg, scion of a prominent Jewish family in Charleston, South Carolina.

It was in the 1930s that Rittenberg rejected a career as a lawyer and became a trade union and civil rights activist. He then went a little further. He became a communist, learnt Chinese, went to China, joined Mao Zedong's guerrillas fighting Chiang Kai-shek's nationalists, emerged after the communist victory as a senior party member close to Mao, ran Radio Peking, translated Mao's thoughts into English, became a leading rabble rouser in the Cultural Revolution - and, by the by, was imprisoned for 16 years in solitary confinement, accused of being a US spy. Then he came back to the US and made a fortune advising American companies on how to get into China.

I first heard of this historical revolutionary figure in China, where he is known as Li Dunbai (it sounds a little like Rittenberg to Chinese ears). To this day, he is taught about in schools as a righteous American who helped build Chinese communism.