Algernon Henry Blackwood (1869–1951) was an English broadcasting narrator, journalist, novelist and short story writer, and 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 that his short story collection Incredible Adventures (1914) "may be the premier weird collection of this or any other century".

Blackwood was born in Shooter's Hill (today part of south-east London, but then part of northwest Kent) and educated at Wellington College. His father was a Post Office administrator who, according to Peter Penzoldt, "though not devoid of genuine good-heartedness, had appallingly narrow religious ideas." Blackwood had a varied career, farming in Canada, operating a hotel, as a newspaper reporter in New York City, and, throughout his adult life, an occasional essayist for various periodicals. In his late thirties, he moved back to England and started to write stories of the supernatural. He was very successful, writing at least ten original collections of short stories and eventually appearing on both radio and television to tell them. He also wrote fourteen novels, several children's books, and a number of plays, most of which were produced but not published. He was an avid lover of nature and the outdoors, and many of his stories reflect this.

H.P. Lovecraft wrote of Blackwood: "He is the one absolute and unquestioned master of weird atmosphere." His powerful story "The Willows," which effectively describes another dimension impinging upon our own, was reckoned by Lovecraft to be not only "foremost of all" Blackwood's tales but the best "weird tale" of all time.

Among his thirty-odd books, Blackwood wrote a series of stories and short novels published as John Silence, Physician Extraordinary (1908), which featured a "psychic detective" who combined the skills of a Sherlock Holmes and a psychic medium. Blackwood also wrote light fantasy and juvenile books.