A new book that offers a surprising reassessment of the Tiananmen Square crackdown through interviews with a disgraced former Beijing mayor went on sale Friday in Hong Kong despite efforts by Chinese authorities to stop the sale. \"Conversations With Chen Xitong,\" which is not available in mainland China, is based on interviews with Chen, who was mayor of Beijing during the 1989 crackdown. Chen has long been portrayed as having supported the military assault, but in the book he says the crackdown was an avoidable tragedy and that he regrets the loss of life, though he denies being directly responsible. Publisher Bao Pu said Thursday that Chinese Communist Party officials had asked the book\'s author, Yao Jianfu, to stop its distribution in Hong Kong, a semiautonomous region of China that enjoys Western-style civil liberties not seen on the mainland, including free speech. The officials said \"they would take care of any financial loss if it is recalled,\" Bao recounts Yao telling him. But by that point, the book had already been sent to shops, so it was \"already a done deal,\" Bao said. There was strong interest in the 267-page book at some Hong Kong bookstores, where sales Friday appeared to be brisk. Staff at the Greenfield Book Store in Mong Kok district said about 40 copies had already been sold by noon. They also reported fielding 70 to 80 phone calls about the book from people speaking both the local Cantonese dialect and Mandarin, which is more common on the mainland. At Cosmos Books in Wan Chai district, a dozen copies were stacked on a table with other books out front, while another two dozen had been set aside for customers to pick up later. Chen was eventually deposed as Beijing\'s Communist Party boss for corruption and is serving a 16-year prison sentence, effectively silencing him. Yao was able to talk with Chen because he was released on medical parole. Chen told Yao that the Tiananmen crackdown should never have happened and that he hoped the government would formally re-evaluate the event, in which the military crushed weekslong protests, killing hundreds, possibly thousands, of people. The book adds to a growing debate ahead of a once-a-decade transfer of power in China later this year from one generation of party leaders to younger successors.