Elizabeth Agassiz, née Cary, was born into a well-connected Boston Brahmin family descended from the earliest settlers of New England. Her parents were Mary Ann Cushing Perkins Cary and her husband Thomas Graves Cary, a businessman. Because of her delicate health, she was tutored at home in childhood. Following the marriage of her older sister Mary to a Harvard professor, she began socializing with a group of intellectuals in Cambridge, and met the Swiss-born naturalist Louis Agassiz. He was married, but his wife died in 1848; Elizabeth married him the following year. The couple opened a pioneering school for girls in their home in Cambridge attended by Clover Adams, among many others. After the school closed in 1863, Elizabeth worked closely with her husband in his scientific research. She organized and documented the Thayer Expedition to Brazil in 1865-1866 and the Hassler Expedition through the Strait of Magellan in 1871-1872. The couple founded the co-educational Anderson School of Natural History, a marine laboratory in Buzzard's Bay. She published several books on natural history, including A First Lesson in Natural History (1859), and Seaside Studies in Natural History (1865), with her stepson Alexander Agassiz. She also published A Journal in Brazil (1867) and The Biography of Louis Agassiz (1885). She helped create the "Harvard Annex" for women in 1879, and was instrumental in transforming it into Radcliffe College in 1894, and served as its first president.