Simon Winchester is a storyteller of rare caliber. The common thread for his diverse biographical sketches is eccentricity, and in his newest book, The Man Who Loved China (Harper Perennial, $15.99), Joseph Needham, Cambridge scientist, leftist, freethinker, accordionist, folk dancer, and nudist, certainly qualifies. A young married Cambridge Fellow, Needham fell in love with a Chinese university student and then in turn became infatuated with and studied the Chinese language, Chinese history, and all the mysteries of the Middle Kingdom.  In 1943, with China in the midst of the Japanese occupation, he made his first of many trips to the country, visits which eventually produced a 24-volume encyclopedia of Chinese civilization. More than 50 years after the passionate love affair began, and two years after his loyal wife died, Needham married the Chinese student. When she died two years later, he asked three other women to marry him.  They all declined.