Pearl Comfort Sydenstricker Buck (June 26, 1892 – March 6, 1973) was an American writer and humanitarian. She is best known for The Good Earth, the best-selling novel in the United States in 1931 and 1932, which won her the Pulitzer Prize in 1932. In 1938, Buck became the first American woman to win the Nobel Prize in Literature "for her rich and truly epic descriptions of peasant life in China" and for her "masterpieces", two memoir-biographies of her missionary parents.

Buck was born in West Virginia, but in October 1892, her parents took their 4-month-old baby to China. As the daughter of missionaries and later as a missionary herself, Buck spent most of her life before 1934 in Zhenjiang, with her parents, and in Nanjing, with her first husband. She and her parents spent their summers in a villa in Kuling, Mount Lu, Jiujiang, and it was during this annual pilgrimage that the young girl decided to become a writer. She graduated from Randolph-Macon Woman's College in Lynchburg, Virginia, then returned to China. From 1914 to 1932, after marrying John Lossing Buck, she served as a Presbyterian missionary, but she came to doubt the need for foreign missions. Her views became controversial during the Fundamentalist–modernist controversy, leading to her resignation.

After returning to the United States in 1935, Buck married the publisher Richard J. Walsh and continued writing prolifically. She became an activist and prominent advocate of the rights of women and racial equality, and wrote widely on Chinese and Asian cultures, becoming particularly well known for her efforts on behalf of Asian and mixed-race adoption.

Originally named Comfort, Pearl Sydenstricker was born in Hillsboro, West Virginia, to Caroline Maude (Stulting) (1857–1921) and Absalom Sydenstricker, of Dutch and German descent respectively. Her parents, Southern Presbyterian missionaries, were married on July 8, 1880 and moved to China shortly thereafter, but returned to the United States for Pearl's birth. When Pearl was five months old, the family returned to China, living first in Huai'an and then in 1896 moving to Zhenjiang, which was then known as Chingkiang in the Chinese postal romanization system, near the major city of Nanjing. In summer, she and her family spent time in Kuling. Her father built a stone villa in Kuling in 1897, and lived there until his death in 1931. It was during this annual summer pilgrimage in Kuling that the young girl decided to become a writer.

Of her siblings who survived into adulthood, Edgar Sydenstricker had a distinguished career with the U.S. Public Health Service and later the Milbank Memorial Fund, and Grace Sydenstricker Yaukey (1899–1994) wrote young adult books and books about Asia under the pen name Cornelia Spencer.

Pearl recalled in her memoir that she lived in "several worlds", one a "small, white, clean Presbyterian world of my parents", and the other the "big, loving merry not-too-clean Chinese world", and there was no communication between them. The Boxer Uprising (1899–1901) greatly affected the family; their Chinese friends deserted them, and Western visitors decreased. Her father, convinced that no Chinese could wish him harm, stayed behind as the rest of the family went to Shanghai for safety. A few years later, Buck was enrolled in Miss Jewell's School in Shanghai, and was dismayed at the racist attitudes there of other students, few of whom could speak any Chinese. Both of her parents felt strongly that Chinese were their equals; they forbade the use of the word heathen, and she was raised in a bilingual environment: tutored in English by her mother, in the local dialect by her Chinese playmates, and in classical Chinese by a Chinese scholar named Mr. Kung. She also read voraciously, especially, in spite of her father's disapproval, the novels of Charles Dickens, which she later said she read through once a year for the rest of her life.

In 1911, Buck left China to attend Randolph-Macon Woman's College in Lynchburg, Virginia, where she graduated Phi Beta Kappa in 1914 and was a member of Kappa Delta sorority.

Although Buck had not intended to return to China, much less become a missionary, she quickly applied to the Presbyterian Board when her father wrote that her mother was seriously ill. In 1914, Buck returned to China. She married an agricultural economist missionary, John Lossing Buck, on May 13, 1917, and they moved to Suzhou, Anhui Province, a small town on the Huai River (not to be confused with the better-known Suzhou in Jiangsu Province). This is the region she describes in her books The Good Earth and Sons.