Dorothy Enid Eden was born in Loburn, near Ashburton, North Canterbury, New Zealand, the fourth child of six of John, a mailman, and Eva Eden. She was baptized as an Anglican. Her paternal grandparents were from Gloucestershire and on her mother's side she was of Danish and Bohemian ancestry. In her infancy her father began farming in Wakanui, and she grew up on the isolated farm with her four sisters and brother Allan (who was to write Islands of Despair, an account of his wartime experiences in the Sub-Antarctic islands). She later told an interviewer: 'My childhood on a lonely New Zealand farm was the most invaluable background for developing imagination ... When I was eight I had measles and went to bed with a copy of Grimm's fairy tales which I read from cover to cover. From that time on I was haunted by this business of suspense ... Dickens ... Mrs Henry Wood ... Jane Eyre'.
Eden attended Wakanui School and Ashburton Technical School, leaving at the age of sixteen to work for an Ashburton lawyer as a typist and later as senior clerk. After eleven years there she moved to Christchurch to work as a legal secretary. From an early age she had wanted to become a writer, enjoying essay writing at school and entertaining the family with her stories. She wrote children's stories for a local farming publication and at twenty-one published her first story for adults, 'Michael and Jennifer' (New Zealand Mirror November 1933); her sister Winifred liked the names so much that she later named her two children Michael and Jennifer. These early stories were published under the name Ena Eden, as she was always known in the family. She continued to write magazine stories until the late 1970s and most of her novels were serialised before publication. She wrote her first book at twenty and sent several manuscripts to English publishers (one lost at sea during the war) before her first book was published in 1940. She travelled extensively after the war and in 1954 settled in London and in time became a full-time writer.
Eden's first books were family dramas, followed by thrillers, then she found her forte, gothic fiction ('mystery plus a touch of the macabre and a slice of melodrama', said one reviewer); later in her career she turned to historical novels and family sagas ('dynastic novels', she called them), with settings as diverse as England, New Zealand, China, Ireland, Denmark, Australia, America, and South Africa during the Boer War, all carefully researched. By 1980 she was among the ten best-selling authors in the world. Her books appeared in English and American editions, hardbacks and paperbacks, with Reader's Digest condensations, large print and Braille editions, and recorded versions on tape. Her first foreign sale was to her ancestral Denmark, and translations followed into many other languages, including Arabic, Chinese, Czech, Danish, Dutch, Estonian, Finnish, Flemish, French, German, Greek, Hebrew, Icelandic, Italian, Japanese, Norwegian, Portuguese, Russian, Slovenian, Spanish, Swedish, Thai, and Turkish. Several of her books were broadcast on radio and at least one, Crow Hollow, was filmed. She returned to New Zealand on a long visit in 1960 at the time of the publication of her New Zealand historical novel Sleep in the Woods.
Many of Eden's literary manuscripts went to Boston University, which established a Dorothy Eden Collection in 1966. Never married, she died of cancer on 4 March 1982 and was buried in London. Obituaries appeared in newspapers worldwide, including the Times, the New York Times and Time magazine. She had suffered for many years from severe arthritis and her will left a substantial donation to aid research into rheumatoid arthritis. Her sister Winifred (to whom Afternoon for Lizards is dedicated) settled in Australia and Eden visited her several times.