In a rare but justified boast Machen stated:

. . . I do not think that anybody before had written anything like the tales of ‘The Black Seal’, or, ‘The White Powder’. The hypothesis on which the former story is based is, of course, not my own: it is that the Fairies, the Little People, were, in fact, the dark, dwarfish, Pre-Celtic inhabitants of Britain. But the supposition that these people still dwell under the hills, that they are horribly evil, and that they are something more—or something less—than human: all this I must put down to my own account. The general hypothesis of ‘The White Powder’ is obtained, very distantly, from Payne Knight; the special machina, the magical division of personality is, to the best of my belief, my own.

Some readers have been puzzled that Machen undermined the stories by revealing them to be merely fabrications of ‘Miss Lally’ and ‘Miss Leicester’—actually the same femme fatale—but in this he was following the scheme of The Dynamiter, in which the protean heroine concocts a series of masquerades.

For years the publisher Grant Richards urged Machen to write a sequel to The Three Impostors, or something in a similar vein, but Machen’s ideas had to come from within himself. And he was determined to move on from imitations of Stevenson. Literature for him was the exploration of ‘the white road’—‘the journey of discovery; the finding of a new world . . . Columbus could not discover America twice’. He told his great friend and companion in the esoteric, A.E. Waite, ‘I shall never give anybody a White Powder again.’

One unhappy consequence of Machen turning away from tales of elemental horror was that Mr Dyson, the amateur sleuth of The Three Impostors and other stories, vanished from his fiction. Dyson, though he is hardly a three-dimensional character, is one of Machen’s most endearing creations; ‘a born meddler in plots and mysteries’, he has a robust approach to literature—in contrast to Machen. Dyson swears he will grow old in ‘the chase of the phrase’, but we are not privileged to see him do so.

Machen set about his literary reformation: there were to be ‘No more white powders, no more of the calix principis inferorum, no more hanky-panky with the Great God Pan, or the Little People . . .’. And after eighteen months of ‘sudores, angores, dolores’ Machen’s greatest gift to the world, The Hill of Dreams (1907), was finished—not that the world wanted it. The London publishers wrote Machen, ‘all implored me, as I loved them, not to publish this book because, as they explained, it was so poor and weak and dull that its publication would ruin what little reputation I had gained before’. It was left to fellow writers many years later to recognise Machen’s achievement. ‘No more wonderful epic of the artist’s soul have I seen till now,’ Henry Miller wrote solemnly, adding, ‘I will not say it is the greatest book written in the English language (that for the idle critics) but I can say that it has bereft me of emotion.’

The story of Lucian Taylor’s quest to ‘win the secret of words’, mirroring Machen’s own battles with language, was completed in 1897. Machen forged ahead on his new path and produced the delicate and decadent short tales in Ornaments in Jade (unpublished until 1924). Although strange sins throng a number of these prose poems, the profound evil of his earlier works is absent. But Machen was too devoted to the gargoyles of art to honour his pledge on horror fiction to the letter. In 1899, after escaping from employment on the periodical Literature, he embarked upon ‘The White People’ (1904), the most spellbinding of all his weird tales, a satanic Alice in Wonderland. It was intended, wrote Machen, ‘to have been something quite long and elaborate and magnificent’, but what emerged was only ‘a broken fragment’.

Yet the story of a young girl’s innocent initiation into sorcery and ancient rites, of how she is drawn into communion with the beautiful yet sinister creatures of the fairy realm, has deservedly been acclaimed as one of the world’s greatest supernatural fictions. Form is impeccably wedded to content in the stream-of-consciousness prose, by turns naive, touching and alarming. Despite his general disappointment with it Machen acknowledged that the story ‘contains some of the most curious work that I have ever done, or ever will do. It goes, if I may say so, into very strange psychological regions’.