The Great God Pan

The Great God Pan is an 1894 horror and fantasy novella by the Welsh writer Arthur Machen. He was inspired to write it by his experiences among the ruins of a pagan temple in Wales, and it was first issued as a chapbook before being collected.

The story begins with an experiment: a doctor named Raymond opens a young woman's mind to what he calls the great god Pan, an operation that leaves her an idiot. Years later a man called Villiers notices a pattern in the deaths and disappearances connected to a woman named Helen Vaughan, and the investigation leads back to that experiment and to something that came into the world through it.

Machen writes in a documentary style, using letters, reports and the accounts of witnesses, so the horror is assembled from what people saw rather than shown directly. The novella is one of the works that shaped horror written in English over the following century, and it is usually named alongside the stories of Poe and the writers who admired him.