The works of Anglo-Welsh author Arthur Machen (1863-1947) made an indelible and ever-expanding impression in the genre of horror and the supernatural, and have always inspired both ardent advocates and determined opponents. In the 1890s, Oscar Wilde, Jerome K. Jerome, and Sir Arthur Conan Doyle admired his work, but the majority of critics were hostile, and he was often seen as part of the Decadent movement of the "Yellow 'Nineties." The first section of this critical anthology provides important contextual information about Machen's life and works, and gives a clear impression of how Machen was regarded in the 1920s, when his books began to emerge from the shadows. The following section offers contributions concerned with Machen's role as a figure of the 1890s and a participant in the Decadent movement. The third section presents discussions Machen's interest in ritual magic, occultism, classical mythology, the sublime, and his own individual and particular form of Christianity. In his later work, Machen never lost his deep interest in folklore and popular customs, eccentric characters and curious historical episodes, and the present volume's final section shows how these continued to inform Machen's work right up until his last writing. In sum total, this volume presents an extended critical assessment of Machen's work, early and late. The volume has been edited by Mark Valentine, a leading authority on Machen, author of Arthur Machen (1995), and editor of Aklo, All Hallows, and Wormwood; and Timothy J. Jarvis, instructor in creative writing and author of the novel The Wanderer (2014) and numerous works of short fiction.