One of the most popular literary figures in American literature is a woman who spent almost half of her long life in China, a country on a continent thousands of miles from the United States. In her lifetime she earned this country’’s most highly acclaimed literary award, the Pulitzer Prize, and also the most prestigious form of literary recognition in the world, the Nobel Prize for literature. Pearl S. Buck was almost a household word throughout much of her life time because of her prolific literary output, which consisted of some eighty-five published works, including several dozen novels, six collections of short stories, four books for children, and more than a dozen works of nonfiction. When she was eighty years old, some twenty-five volumes were awaiting publication. Many of those books were set in China, the land in which she spent so much of her life. Her books and her life served as a bridge between the cultures of the East and the West. As the product of those two cultures she became, as she described herself, "mentally bifocal". Her unique background made her into an unusually interesting and versatile human being. As we examine the life of Pearl Buck, we cannot help but be aware that we are in fact meeting three separate people, a wife and mother, an internationally famous writer, and a humanitarian and philanthropist (慈善家). One cannot really get to know Pearl Buck without learning about each of the three. Though honored in her lifetime with the William Dean Howell Medal of the American Academy of Arts and Letters in addition to the Nobel and Pulitzer prizes, Pearl Buck as a total human being, not only a famous author, is a captivating subject of study. What is the main purpose of the passage