Helen Beatrix Potter (28 July 1866 – 22 December 1943) was an English author, illustrator, mycologist, and conservationist who was best known for her children's books, which featured animal characters such as Peter Rabbit. Born into a privileged household, Potter was educated by governesses, and grew up isolated from other children. She had numerous pets and through holidays in Scotland and the Lake District developed a love of landscape, flora and fauna, all of which she closely observed and painted. As a young woman her parents discouraged intellectual development, but her study and paintings of fungi led her to be widely respected in the field of mycology. In her thirties Potter published the highly successful children's book The Tale of Peter Rabbit, and became secretly engaged to her publisher, Norman Warne, causing a breach with her parents, who disapproved of his social status. Warne died before the wedding could take place. Potter eventually published 23 children's books, and having become financially independent of her parents, was able to buy a farm in the Lake District, which she extended with other purchases over time. In her forties she married a local solicitor, William Heelis. She became a sheep breeder and farmer while continuing to write and illustrate children's books. Potter died in 1943, and left almost all of her property to The National Trust in order to preserve the beauty of the Lake District as she had known it, protecting it from developers.
Potter's books continue to sell well throughout the world, in multiple languages. Her stories have been retold in various formats, including a ballet, films and in animation.

Beatrix Potter was born in South Kensington, London on 28 July 1866. Educated at home by a succession of governesses, she had little opportunity to mix with other children. Even Potter's younger brother, Bertram, was rarely at home; he was sent to boarding school, leaving Beatrix alone with her pet animals. She had frogs, newts, ferrets and even a pet bat. She also had two rabbits — the first was Benjamin, whom she described as "an impudent, cheeky little thing", while the second was Peter, whom she took everywhere with her, even on the occasional outings, on a little lead. Potter would watch these animals for hours on end, sketching them. Gradually the sketches became better and better, developing her talents from an early age.
Beatrix Potter's father, Rupert William Potter (1832–1914), although trained as a barrister, spent his days at gentlemen's clubs and rarely practised law. Her mother, Helen Potter née Leech (1839–1932), the daughter of a cotton merchant, spent her time visiting or receiving visitors. The family was supported by both parents' inherited incomes.
Every summer, Rupert Potter would rent a country house; firstly Dalguise House in Perthshire, Scotland for the eleven summers of 1871 to 1881, then later one in the English Lake District. In 1882 the family met the local vicar, Canon Hardwicke Rawnsley, who was deeply worried about the effects of industry and tourism on the Lake District. He would later found the National Trust in 1895, to help protect the countryside. Beatrix Potter had immediately fallen in love with the rugged mountains and dark lakes, and through Rawnsley, learnt of the importance of trying to conserve the region, something that was to stay with her for the rest of her life. When Potter came of age, her parents appointed her their housekeeper and discouraged any intellectual development, instead requiring her to supervise the household. From the age of 15 until she was past 30, she recorded her everyday life in journals, using her own secret code which was not decoded until 20 years after her death. An uncle attempted to introduce her as a student at the Royal Botanic Gardens at Kew, but she was rejected because she was female. Potter was later one of the first to suggest that lichens were a symbiotic relationship between fungi and algae. As, at the time, the only way to record microscopic images was by painting them, Potter made numerous drawings of lichens and fungi. As the result of her observations, she was widely respected throughout England as an expert mycologist. She also studied spore germination and life cycles of fungi. Potter's set of detailed watercolours of fungi, numbering some 270 completed by 1901, is in the Armitt Library, Ambleside.
In 1897, her paper on the germination of spores was presented to the Linnean Society by her uncle Sir Henry Enfield Roscoe, as women were barred from attending meetings. (In 1997, the Society issued a posthumous official apology to Potter for the way she had been treated.) The Royal Society also refused to publish at least one of her technical papers. She also lectured at the London School of Economics several times. The basis of her many projects and stories were the small animals that she smuggled into the house or observed during family holidays in Scotland and the Lake District. When she was 27 and on one such holiday in Scotland, in a letter dated 4 September 1893 she sent a story about rabbits to Noel Moore, the five-year-old son of her last governess. She was encouraged to publish the story so she borrowed it back in 1901 and made it into the book entitled The Tale of Peter Rabbit. However, she struggled to find a publisher for it and eventually had 250 copies printed privately. In October 1902, Frederick Warne & Co. agreed to publish 8,000 copies in a small format, easy for a child to hold and read, having asked Beatrix to re-illustrate it in color. It was extremely well received and, by the end of the year, 28,000 copies had been printed.

She followed it with The Tale of Squirrel Nutkin in 1903, that was also based on an earlier letter. Such was the popularity of these and her subsequent books that she gained an independent income from their sales. She also became secretly engaged to the publisher, Norman Warne in 1905, but her parents were set against her marrying a tradesman. Their opposition to the wedding caused a breach between Beatrix and her parents. However, the wedding was not to be, for soon after the engagement, Norman fell ill of pernicious anemia and died within a few weeks. Beatrix was devastated. She wrote in a letter to his sister, Millie, "He did not live long, but he fulfilled a useful happy life. I must try to make a fresh beginning next year." Potter eventually wrote 23 books, all in the same small format. Her writing efforts finally abated around 1920 due to poor eyesight. The Tale of Little Pig Robinson was published in 1930; however, the actual manuscript was one of the first to be written and far predates this publication date. After Warne's death, Potter purchased Hill Top Farm in the village of Sawrey, Cumbria, in the Lake District. She loved the landscape, and visited the farm as often as she could, discussing the set-up with farm manager John Cannon. With the steady stream of royalties from her books, she began to buy pieces of land under the guidance of local solicitor William Heelis. In 1913 at the age of 47, Potter married Heelis and moved to Hill Top Farm permanently. Some of Potter's best loved works show the Hill Top Farm farm house and the village. While the couple had no children, the farm was constantly alive with dogs, cats and even a pet hedgehog named "Mrs. Tiggy-Winkle". On moving to the Lake District, Potter became engrossed in breeding and showing Herdwick sheep. She became a respected farmer, a judge at local agricultural shows, and President of the Herdwick Sheep Breeders' Association. When Potter's parents died, she used her inheritance to buy more farms and tracts of land. After some years Potter and Heelis moved down into the village of Sawrey, and into Castle Cottage — where the local children knew her for her grumpy demeanour, and called her "Auld Mother Heelis". Her letters of the time reflect her increasing concerns with her sheep, preservation of farmland, and World War II. Beatrix Potter died at Castle Cottage in Sawrey on 22 December 1943. Her body was cremated at Carleton Crematorium, Blackpool, and her ashes were scattered in the countryside near Sawrey. In her will, Potter left almost all of her property to the National Trust — 4,000 acres (16 km²) of land, cottages, and 15 farms. The legacy has helped ensure that the Lake District and the practice of fell farming remain unspoiled to this day. Her properties now lie within the Lake District National Park. The Trust's 2005 Swindon headquarters are named "Heelis" in her honour.