Frances (Fanny) Matilda Van de Grift Osbourne Stevenson (10 March 1840 – 18 February 1914) was an American magazine writer. She became a supporter and later wife of Robert Louis Stevenson, and the mother of Isobel Osbourne, Samuel Lloyd Osbourne, and Hervey Stewart Osbourne.
Fanny Vandegrift was born in Indianapolis, the daughter of builder Jacob Vandegrift, and his wife Esther Thomas Keen. She was something of a tomboy, and had dark curly hair. At the age of seventeen she married Samuel Osbourne, a lieutenant on the State Governor's staff.  Their daughter Isobel (or 'Belle') was born the following year.
Samuel fought in the American Civil War, went with a friend sick with tuberculosis to California, and via San Francisco, he ended up in the silver mines of Nevada. Once settled there he sent for his family. Fanny and the five-year-old Isobel made the long journey via New York, the isthmus of Panama, San Francisco, and finally by wagons and stage-coach to the mining camps of the Reese River, and the town of Austin in Lander County. Life was difficult in the mining town, and there were few women around. Fanny learned to shoot a pistol and to roll her own cigarettes.
The family moved to Virginia City, Nevada and it was whilst living here that Samuel began to be unfaithful to Fanny.  In 1866 he headed off gold prospecting in the Coeur d'Alene Mountains, and Fanny and her daughter journeyed to San Francisco.  There was a rumour that Sam had been killed by a grizzly bear, but he returned to the family safe, and a second child Samuel Lloyd was born in 1868. But Samuel continued philandering and Fanny returned to Indianapolis.
The couple were reconciled again in 1869, and lived in Oakland where a second son, Hervey, was born. Fanny took up painting and gardening. However, Sam's behaviour did not improve, and Fanny finally left him in 1875 and moved with her three children to Europe. They lived in Antwerp for three months, and then to allow Fanny to study art, they moved to Paris where Fanny and Isobel both enrolled in the Académie Julian. Hervey, sick with scrofulous tuberculosis, died on 5 April 1876, and was buried in a temporary grave at Père Lachaise Cemetery. 
After Hervey's death, Fanny moved to Grez-sur-Loing, where she met and befriended Robert Louis Stevenson. A 1916 recollection of her by Mr Birge Harrison (published in the Centenary Magazine) recalls "That she was a woman of intellectual attainments is proved by the fact that she was already a magazine writer of recognized ability, and that at the moment when Stevenson first came into her life she was making a living for herself and her two children with her pen."  Convinced of his talent, she encouraged and inspired him. He became deeply attached to her, but Fanny returned abruptly to California. 
In 1878 Fanny cabled Stevenson that she planned to leave her husband. Stevenson announced his intention of following her, but his parents refused to pay for it, so he saved for three years to pay his own way. In 1879, despite protests of family and friends, Stevenson went to Monterey, California, where Fanny was recovering from an emotional breakdown related to indecision about whether to leave her philandering husband.  Stevenson wrote many of his most 'muscular' essays in Monterey while awaiting Fanny's decision.
The lady ultimately chose Stevenson, divorced Osbourne, and in May 1880 she and Stevenson were married in San Francisco. A few days later, the couple left for a honeymoon in the Napa Valley, where Stevenson produced his work Silverado Squatters. He later wrote The Amateur Emigrant in two parts about his passage to America: From the Clyde to Sandy Hook and Across the Plains. His middle-class friends were shocked by his travel with the lower classes; it was not published in full in his lifetime, and his father bought up most copies.
In August 1880, the family moved to Great Britain, where Fanny helped to patch things up between Robert and his father. Always in search of a climate conducive to Stevenson's ailing health, the couple travelled to the Adirondacks in the US. In 1888, they chartered the Casco out of San Francisco and sailed to Western Samoa. Later voyages on the Equator and Janet Nicoll with Fanny's son Lloyd Osbourne followed. They settled in Upolu, at their home Vailima, where Stevenson died on 3 December 1894.
Return to California
After Stevenson's death, Fanny returned to California to begin a new life in America and Europe with an adoring companion decades her junior, newsman Ned Field.
When Fanny died in Santa Barbara, California, Edward Salisbury Field, her last companion-in-adventure, described her as "the only woman in the world worth dying for." Soon after, he married her daughter Isobel Osbourne. In 1915, Fanny's ashes were taken by her daughter to Samoa where they were interred next to Stevenson on top of Mount Vaea. The bronze plaque for Fanny bears her Samoan name 'Aolele' (Flying Cloud in Samoan).
The actress Aline Towne played Fanny in the 1958 episode, "The Great Amulet," of the syndicated television anthology series, Death Valley Days, hosted by Stanley Andrews. The episode focuses on Fanny and Robert Louis Stevenson, a role played by Don Reardon. The "Great Amulet" is revealed at the conclusion of the episode.
- ‘Too Many Birthdays’ (St. Nicholas, 1878)
- ‘Sargent’s Rodeo’ (Lippincot’s Magazine, Jan. 1880)
- ‘Chy Lung, The Chinese Fisherman’ (St. Nicholas, 1880)
- ‘The Warlock’s Shadow’ (Belgravia, 1886)
- ‘Miss Pringle’s Neighbors’ (Scribner’s Magazine, 1887)
- ‘The Nixie’ (Scribner’s Magazine, 1888)
- ‘The Half-White’ (Scribner’s Magazine, 1891)
- ‘Under Sentence of the Law: The Story of a Dog’ (McClure’s, 1893)
- ‘Anne’ (Scribner’s Magazine, 1899)
With Robert Louis Stevenson
The Cruise of the Janet Nicol (1914 - published posthumously)
- "A Dangerous Collaboration - Dangerous Women Project". Dangerous Women Project. 6 January 2017. Retrieved 13 November 2018.
- "Fanny Stevenson's short stories". EdRLS. 27 February 2012. Retrieved 13 November 2018.
- The Life of Mrs. Robert Louis Stevenson by Nellie Van de Grift Sanchez.
- "Fanny Stevenson - Robert Louis Stevenson Museum". Robert Louis Stevenson Museum. Retrieved 13 November 2018.
- "Fanny Van de Grift Stevenson – Deciphering The Dynamiter". thedynamiter.llc.ed.ac.uk. Retrieved 13 November 2018.
- In the South Seas (1896) & (1900) Chatto & Windus; republished by The Hogarth Press (1987). A collection of Stevenson's articles and essays on his travels in the Pacific
- The Cruise of the Janet Nichol Among the South Sea Islands, A Diary by Mrs Robert Louis Stevenson, Charles Scribner's Sons, New York, 1914, republished 2004, editor, Roslyn Jolly (U. of Washington Press/U. of New South Wales Press)
- Terry, Reginald Charles (1996). Robert Louis Stevenson: interviews and recollections. University of Iowa Press. p. 207. ISBN 0-87745-512-0. Retrieved 1 July 2010.
- Yousef, Robyn (26 March 2013). "Samoa: Tales of the teller live on". New Zealand Herald. ISSN 1170-0777. Retrieved 29 November 2016.
- "The Great Amulet on Death Valley Days". Internet Movie Data Base. Retrieved 1 September 2018.
- Dead Man's Chest: Travels after Robert Louis Stevenson, Nicholas Rankin, ISBN 0-571-13808-X
- Tales of Love and Hate in Old San Francisco, Millie Robbins. Chronicle Books, San Francisco 1971. ASIN B0006C0QVA
- Robert Louis Stevenson's Ethics for Rascals, Elayne Wareing Fitzpatrick, Xlibris Books, Philadelphia, 2000. ISBN 0-7388-3548-X[self-published source]
- Fanny Stevenson: Muse, Adventuress and Romantic Enigma, Alexandra Lapierre. Carroll & Graf, N.Y., 1995. ISBN 978-1857023824