Mary Blair Rice, better known by the pen name Blair Niles (1880–1959) was an American novelist and travel writer. She was a founding member of the Society of Woman Geographers. The name Blair Niles was adopted in part from the surname of her late second husband, Robert Niles, Jr.
Blair Niles was the grand-daughter of Sara Rice Pryor and Roger Pryor, and the daughter of Marie Gordon Pryor. Her unique namesake, "Mary Blair," is shared with her mother's sister, Mary Blair Pryor, her cousin Mary Blair Walker Zimmer, and several other women in her lineage, as documented in *"Mary Blair Destiny".  Her grandmother Sara Rice Pryor was also a widely-read author for her chronicling of life in antebellum Virginia. Blair Niles did not have any children of her own.
The first wife of oceanographer William Beebe, Niles also wrote under the name of Mary Blair Beebe. She lived among indigenous peoples in Mexico, South America, and Southeast Asia. In 1923, she published Casual Wanderings in Ecuador. Colombia: Land of Miracles followed in 1924, and Peruvian Pageant in 1937. In these books she linked contemporary culture with the past by exploring history, traditions, and legends. She visited the notorious Devil's Island in 1926 and recorded the life of a prisoner there (René Belbenoit) in her 1928 best selling biography: Condemned to Devil's Island. The international sensation caused by this book led to prison reforms. Her 1931 book, Strange Brother, was a gay-themed novel (her only work in that genre) set in New York City during the Harlem Renaissance.
- Casual Wanderings in Ecuador (1923)
- Colombia: Land Of Miracles (1924)
- Black Haiti: A Biography of Africa's Eldest Daughter (1926)
- Peruvian Pageant, A Journey In Time (1937)
- The James: From Iron Gate to the Sea (1939) (Rivers of America Series)
- Passengers to Mexico: The Last Invasion of the America's (1943)
- Martha's Husband: An Informal Portrait of George Washington (1951)
- Condemned to Devil's Island (1928) - turned into the 1929 film Condemned
- Free (1930)
- Strange Brother (1931)
- Maria Paluna (1934)
- Day of the Immense Sun (1936)
- East by Day (1941)
- Slide, Anthony. Lost Gay Novels: A Reference Guide to Fifty Works from the First Half of the Twentieth Century, (Binghamton, NY: Harrington Park Press), page 137.
- Richman, Erin Mary Blair Destiny, Two Goddesses Publishing, page 41-42 ISBN 978-1-7330180-0-5.
- Stryker, Susan (2001). Queer Pulp: Perverted Passions from the Golden Age of the Paperback (1st ed.). San Francisco: Chronicle Books. p. 97. ISBN 978-0-8118-3020-1.
- "Mary Blair Destiny" by Erin L. Richman.
- Works by or about Blair Niles at Internet Archive
- Works by Blair Niles at LibriVox (public domain audiobooks)
- NILES, Blair (1880-1959) (rootsweb.com)
- Society of Woman Geographers (iswg.org)
- Antiquarian Books (addall.com)