The Great God Pan
What is now the first chapter of the novella was published in 1890 in a magazine called "The Whirlwind", while what is now the third chapter of the book was published in the same magazine the following year as a standalone short story called "The City of Resurrections". Machen only viewed the two works as connected after they were finished. Once he decided the two stories were connected, Machen wrote the rest of "The Great God Pan" in a single evening save for its final chapter. Machen did not think of an ending for the tale for months, and in that time believed that the novella would remain unfinished forever. The last chapter was completed in June 1891. Machen sent the novella to the publisher Blackwood, who rejected it, deeming it a clever story that "shrink[s]...from the central idea." It was accepted by John Lane and published in 1894. When published as a book, "The Great God Pan" was accompanied by another Machen tale called "The Inmost Light" which also features a mad scientist and elements of science fiction. The book's cover was illustrated by Aubrey Beardsley.
The Great God Pan
In a review of the novella for "Black Gate", Matthew David Surridge hypothesized that Machen took inspiration from Mary Shelley's "Frankenstein" (1818) in his portrayal of Dr. Raymond as a mad scientist akin to Victor Frankenstein. The works of Robert Louis Stevenson, especially his 1886 novella "Strange Case of Dr Jekyll and Mr Hyde", were among Machen's most significant influences when writing "The Great God Pan". Critic John Gawsworth also sees Machen's novella as reminiscent of the horror stories of Edgar Allan Poe and Sheridan Le Fanu. Aaron Worth noted similitude between the death of Helen Vaughan and the theories of alchemist Thomas Vaughan, who is the character's namesake and Helen's disintegration recalls the alchemical concept of the prima materia. John C. Tibbetts observes similarities between Helen Vaughan and Ayesha, the sexually liberated demonic priestess from H. Rider Haggard's "" (1886). Machen wrote that several critics felt that Joris-Karl Huysmans's novels "À rebours" (1884) and "Là-bas" (1891) had inspired "The Great God Pan", though he did not read either book until after "Pan" was published. Upon reading the two novels, Machen concluded that "my critics had not read them either."