THE Chinese Communist Party is to publish My Father, Deng Xiaoping, a biography by his youngest daughter, Xiao Rong, next month, fuelling speculation about the health of the patriarch. To be published by the Central Party Literature Publishing House, the 460,000-word account of the pre-1949 life of Mr Deng is seen as the most authoritative portrait of the patriarch, who will turn 89 on August 22. Ms Xiao, who has served as the ''ears and eyes'' of her father in recent years, has said she will also write about the rest of her father's life. The Liberation Army Daily published a 11/2-page interview with the book's editor and brief excerpts. Hong Kong's Wen Wei Po and Ta Kung Pao also published previews of the biography at the weekend. A Chinese analyst said it was unusual for a family member of a Chinese leader to publish a biography. ''If Deng were physically strong, he might not have agreed to it. There might be something wrong with his health,'' he said. Speculation about Mr Deng's health has become intense in the past few weeks. Quoting intelligence sources in Beijing, some United States media said last week that Mr Deng was on his death bed. But senior party leader Qiao Shi denied the report during a visit to Singapore. Ms Xiao has written short articles about her father's life, which have been carried in Chinese journals. But this will be the first comprehensive biography by a family member of Mr Deng. In her postscript, she wrote: ''I have to write about my father because I'm always by his side and I think I understand him.'' Mr Deng, who is against gaining a cult following, has never written his memoirs and previously allowed relatively little to be published in China about his personal life. In Ms Xiao's book, however, she reveals that he developed a taste for cheese, wine, coffee and other French food during his six years of study and work in France in the 1920s along with the late premier, Zhou Enlai. She also confirms rumours that Mr Deng, whose first wife died in childbirth in 1930, had a second wife who divorced him when he was in political trouble in 1933. He married his present wife, Zhuo Lin, in 1939, and had five children with her. Ms Xiao wrote in her postscript that she would record the latter half of Mr Deng's life, which she described as the ''most glorious chapter'', in another book. Whether the more sensitive parts of his dramatic political career, during which he was twice purged by Mao Zedong but came back to succeed him and undo many of his policies, will be included remains unknown. In the Liberation Army Daily, Ms Xiao quoted Mr Deng as saying at lunch on the first day after his official retirement on November 8, 1989: ''After I retire, what I want most is to lead the life of an ordinary person - to live more simply, to be able to take walks on the street and go touring.'' Ms Xiao said: ''But the wish has yet to be granted.'' She added: ''In 1997, he wants to set foot in Hong Kong, when it returns to the motherland. ''He has said that he has to go, even if he is in his wheelchair, to stand on this piece of the motherland for just one minute.''