Algernon Henry Blackwood (14 March 1869 – 10 December 1951) was an English broadcasting narrator, journalist, novelist, and short story writer. He was among the most prolific ghost story writers in the history of the genre. The literary critic S. T. Joshi stated, "His work is more consistently meritorious than any weird writer's except Dunsany's" and referred to his short story collection Incredible Adventures (1914) as "the premier weird collection of this or any other century."

Born and raised in England during the late Victorian and early Edwardian periods, Blackwood spent his early adult life in a variety of occupations in Canada and the U.S.A. before returning to England. A lifelong bachelor, his fascination with the supernatural and mysticism was reflected in many of his writings, influencing numerous 20th-century science fiction and fantasy writers.