A Welsh author and translator with a mystic, gothic bent, he wrote The Great God Pan and The Hill of Dreams. His other supernaturally-themed works include The Shining Pyramid and The Terror.
His birth name was Arthur Llewelyn Jones, and he came from a family of clergymen. He failed his medical school entrance exams before settling on a literary career.
He joined a company of traveling actors in 1901 as a means of distracting himself from his grief over the death of his first wife.
He married music and theatre enthusiast, Amelia (Amy) Hogg, in 1887. After Hogg's untimely death from cancer, Machen wed Dorothie Purefoy Hudleston.
His work was greatly admired by Oscar Wilde.