The author, a journalist, is a third-generation Chinese-Canadian and her book is sub-titled, "Searching for Forgiveness in Beijing." In 1972, as an ardent young Maoist at McGill University, she was invited to spend a year at Beijing University. During her time there she got to know a fellow student, a Chinese girl called Yin, who had confided in her that she wanted to visit America. Such an aspiration in Mao’s China was tantamount to treason. Wong, who by her own admission was a "‘True Believer’: fanatic, ignorant and adolescent", informed on her acquaintance to the authorities.

For many years, absorbed in a successful career as a foreign correspondent, Wong forgot her youthful betrayal. Then, discovering her student diary of her Beijing sojourn, she was confronted by this buried memory and stricken with remorse. What if her action had "thoughtlessly destroyed a young woman I didn’t even know"? With husband and two teenage sons in tow, she returns to Beijing three decades later and the seemingly impossible task of tracking down Yin.

Here the title is apt. After the Cultural Revolution – in full swing in 1972 – was over, the Chinese deliberately erased it from history and public consciousness. Former students Wong had known were reluctant to talk, even when she was able to track them down; "pretending nothing happened is perhaps the only way to cope". Finally, almost miraculously, there is a breakthrough; she meets the victim of her thoughtless action and apologises several times. Yin, who had changed her name to Lu Yi, forgives her and tells her story. Apparently, Wong’s accusation had been only one of 30 "crimes" she had been accused of at that time; she had been forced to leave the university and do hard labour in a remote province. Pardoned years later, she had become a successful lawyer and had even made the longed-for trip to America. So the story ends happily.

Much of the book concerns Wong’s struggle to understand her own behaviour: why had this "middle-class Montreal Maoist" thrown herself so enthusiastically into the Cultural Revolution and why had she held so stubbornly to the view that Mao’s version of socialism was so superior to the capitalist system at home? The Communists, she argues, did eliminate the triads, the local militia, the armed thugs and the prostitutes; they had built roads, reservoirs and irrigation systems. They had forced their creaking civilization into the 20th century. Yet the author does not examine what cost in human lives this might have entailed.

Alongside her quest for Yin, Wong treats the reader to a vivid and humorous description of modern Beijing: seemingly a vast and heavily polluted building site, with permanent smog and surveillance. It is clear that the huge city must have done a Potemkin village-type makeover before the Olympics. I read the book during the 20th anniversary of the Tiananmen Square massacre of June 4, 1989. This, the author discovers, is also never spoken about; indeed, a whole new generation, preferring pop music and dancing, knows nothing about the ultimate sacrifice made in the name of freedom by their student precursors. One of her former tutors at Beijing University, whom she nicknames "Fu the Enforcer", laments that whereas in the old days the dominant motto of the student society was "‘serve the people’, now there is a spiritual crisis. People have no goal except to get rich."

There are also those she terms the "walking wounded", the older generation who suffered during Mao’s long and violent regime, yet who prefer to bury their memories rather than speak of them. Their scars run too deep for excavation and analysis. The author herself has embarked on a worthy journey: to atone for past wrong-doing, however excusable it might have been at the time. The narrative is written in a jaunty style, as well it might be; when Wong began her book, she of course already knew its ending. One wonders what she would have written and indeed, whether she would have written at all, if she had learnt that she really had been responsible for destroying the life of another student. It would have been a different and a darker territory; indeed, the stuff of literature rather than this lively travelogue.

Francis Phillips writes from Buckinghamshire, in the UK.