[citation needed] Local historian and folklorist Fred Hando suggests Machen's early interest in the occult came from an article of alchemy in a volume of Household Words in his father's library.

[1] In 1887, the year his father died,[3] Machen married Amelia (Amy) Hogg, an unconventional music teacher with a passion for the theatre, who had literary friends in London's bohemian circles.

[5] Around 1890 Machen began to publish in literary magazines, writing stories influenced by the works of Robert Louis Stevenson, some of which used gothic or fantastic themes.

[7] Machen's recovery was further helped by his sudden change of career, becoming an actor in 1901 and a member of Frank Benson's company of travelling players, a profession which took him round the country.

In 1906 Machen's literary career began once more to flourish as the book The House of Souls collected his most notable works of the nineties and brought them to a new audience.

Publishing his views in Lord Alfred Douglas's The Academy, for which he wrote regularly, Machen concluded that the legends of the Grail actually were based on dim recollections of the rites of the Celtic Church.

[5] The next few years saw Machen continue with acting in various companies and with journalistic work, but he was finding it increasingly hard to earn a living and his legacies were long exhausted.

He published a series of stories capitalizing on this success, most of which were morale-boosting propaganda, but the most notable, "The Great Return" (1915) and the novella The Terror (1917), were more accomplished.

The Secret Glory, considered by some to be Machen's final masterpiece,[10] was belatedly published, as well as the autobiographical Far Off Things and new editions of his Casanova translation, The House of Souls and The Hill of Dreams.

Machen's works had now found a new audience and publishers in the United States, and a series of requests for republications of books started to come in.

The initial names on the appeal show the general recognition of Machen's stature as a distinguished man of letters, as they included Max Beerbohm, T. S. Eliot, Bernard Shaw, Walter de la Mare, Algernon Blackwood, and John Masefield.

Machen's later works became somewhat less obviously full of gothic trappings, but for him investigations into mysteries invariably resulted in life-changing transformation and sacrifice.

[11] His main passions were for writers and writing he felt achieved this, an idiosyncratic list which included the Mabinogion and other medieval romances, François Rabelais, Miguel de Cervantes, William Shakespeare, Samuel Johnson, Thomas de Quincey, Charles Dickens, Arthur Conan Doyle, Edgar Allan Poe, and Robert Louis Stevenson.

He was deeply suspicious of science, materialism, commerce, and Puritanism, all of which were anathema to Machen's conservative, bohemian, mystical, and ritualistic temperament.

[citation needed] Machen, brought up as the son of a Church of England clergyman, always held Christian beliefs, though accompanied by a fascination with sensual mysticism; his interests in paganism and the occult were especially prominent in his earliest works.

Machen was well read on such matters as alchemy, the kabbalah, and Hermeticism, and these occult interests formed part of his close friendship with A. E. Waite.

He stated in response to a 1937 questionnaire on the Spanish Civil War in the Left Review, "Mr. Arthur Machen presents his compliments and begs to inform that he is, and always has been, entirely for General Franco.

[14] Literary critics such as Wesley D. Sweetser and S. T. Joshi see Machen's works as a significant part of the late Victorian revival of the gothic novel and the decadent movement of the 1890s, bearing direct comparison to the themes found in contemporary works like Robert Louis Stevenson's Strange Case of Dr Jekyll and Mr Hyde, Bram Stoker's Dracula, and Oscar Wilde's The Picture of Dorian Gray.

[15] Historian of fantastic literature Brian Stableford has suggested that Machen "was the first writer of authentically modern horror stories, and his best works must still be reckoned among the finest products of the genre".

Machen's story "The White People" includes references to curious unknown rites and beings, an idea Lovecraft uses frequently in the mythos.

Lovecraft pays tribute to the influence by directly incorporating some of Machen's creations and references, such as Nodens and Aklo, into his Cthulhu Mythos and using similar plotlines, most notably seen by a comparison of "The Dunwich Horror" to The Great God Pan and of "The Whisperer in Darkness" to "The Novel of the Black Seal".

Other Lovecraft tales with a debt or reference to Machen include "The Call of Cthulhu", "The Festival", "Cool Air", "The Descendant", and "The Colour Out of Space".

[citation needed] His intense, atmospheric stories of horror and the supernatural have been read and enjoyed by many modern horror and fantasy writers, influencing directly Peter Straub, Stephen King, Ramsey Campbell, Karl Edward Wagner,[21] "Sarban" (John William Wall),[22] Joanna Russ,[23] Graham Joyce, Simon Clark, Tim Lebbon, and T. E. D. Klein, to name but a few.

He was also a major influence on Paul Bowles and Javier Marías, the latter of whom dedicated a subplot of his 1989 novel All Souls to collecting the works of Machen and his circle of peers.

He was one of the most significant figures in the life of the Poet Laureate Sir John Betjeman, who attributed to Machen his conversion to High Church Anglicanism, an important part of his philosophy and poetry.

In music, the composer John Ireland found Machen's works to be a life-changing experience that directly influenced much of his composition[26] – specifically the piano piece The Scarlet Ceremonies (1912–13, founded on a quotation from "The White People"); the symphonic rhapsody Mai-Dun (1920–21, believed to have been inspired by The Hill of Dreams); and Legend for piano and orchestra (1933), which is dedicated to Machen.

Other notable figures with an enthusiasm for Machen have included Brocard Sewell, Barry Humphries, Stewart Lee and Rowan Williams, Archbishop of Canterbury.

It fosters interest not only in Machen but in events in which he played a key part, such as the Angels of Mons affair, and organises psychogeographic excursions.