Rachel Louise Carson (May 27, 1907 – April 14, 1964) was an American marine biologist, writer, and conservationist whose sea trilogy (1941–1955) and book Silent Spring (1962) are credited with advancing marine conservation and the global environmental movement.

Carson began her career as an aquatic biologist in the U.S. Bureau of Fisheries, and became a full-time nature writer in the 1950s. Her widely praised 1951 bestseller The Sea Around Us won her a U.S. National Book Award, recognition as a gifted writer, and financial security. Its success prompted the republication of her first book, Under the Sea Wind (1941), in 1952, which was followed by The Edge of the Sea in 1955 — both were also bestsellers. This sea trilogy explores the whole of ocean life from the shores to the depths.

Late in the 1950s, Carson turned her attention to conservation, especially some problems she believed were caused by synthetic pesticides. The result was the book Silent Spring (1962), which brought environmental concerns to an unprecedented share of the American people. Although Silent Spring was met with fierce opposition by chemical companies, it spurred a reversal in national pesticide policy, which led to a nationwide ban on DDT and other pesticides. It also inspired a grassroots environmental movement that led to the creation of the U.S. Environmental Protection Agency. Carson was posthumously awarded the Presidential Medal of Freedom by President Jimmy Carter.

Carson was born on May 27, 1907, on a family farm near Springdale, Pennsylvania, located by the Allegheny River near Pittsburgh. She was the daughter of Maria Frazier (McLean) and Robert Warden Carson, an insurance salesman. She spent a lot of time exploring around her family's 65-acre (26 ha) farm. An avid reader, she began writing stories, often involving animals, at age eight. At age ten, she had her first story published. She enjoyed reading St. Nicholas Magazine, which carried her first published stories, the works of Beatrix Potter, the novels of Gene Stratton-Porter, and in her teen years, Herman Melville, Joseph Conrad, and Robert Louis Stevenson. The natural world, particularly that of the ocean, was the common thread of her favorite literature. Carson attended Springdale's small school through tenth grade, and then completed high school in nearby Parnassus, Pennsylvania, graduating in 1925 at the top of her class of 44 students. In high school, Carson was said to have been somewhat of a loner.

Carson gained admission to Pennsylvania College for Women, now Chatham University, in Pittsburgh, where she originally studied English but switched her major to biology in January 1928. She continued contributing to the school's student newspaper and literary supplement.

She was admitted to graduate school at Johns Hopkins University in Baltimore in 1928, but was forced to remain at the Pennsylvania College for Women for her senior year due to financial difficulties. In 1929, she graduated magna cum laude. After a summer course at the Marine Biological Laboratory, she continued her studies in zoology and genetics at Johns Hopkins in the fall of 1929. After her first year of graduate school, Carson became a part-time student, taking an assistantship in Raymond Pearl's laboratory, where she worked with rats and Drosophila, to earn money for tuition. After false starts with pit vipers and squirrels, she completed a dissertation on the embryonic development of the pronephros (urinary organ) in fish.

In June 1932, she earned a master's degree in zoology. She had intended to continue for a doctorate, however in 1934 Carson was forced to leave Johns Hopkins to search for a full-time teaching position to help support her family during the Great Depression. In 1935, Carson's father died suddenly, worsening their already critical financial situation and leaving Carson to care for her aging mother.

At the urging of Mary Scott Skinker, her undergraduate biology mentor, Carson secured a temporary position with the U.S. Bureau of Fisheries, where she wrote radio copy for a series of weekly educational broadcasts called Romance Under the Waters. The series of 52 seven-minute programs focused on aquatic life and was intended to generate public interest in fish biology and the bureau's work, a task that several writers before Carson had not managed. Carson also began submitting articles on marine life in the Chesapeake Bay, based on her research for the series, to local newspapers and magazines. Carson earned extra money as a lecturer at the University of Maryland's Dental and Pharmacy Schools and Johns Hopkins University.