Why is studious, bookish, quiet Lawrence Hillyer suddenly reviled and shunned by his fellow holiday-makers at a genteel Pembrokeshire coastal resort? Why is staunch and respectable Mrs Jolly, a landlady of many years seniority, all at once the source of police interest and knowing looks from her neighbours? What weird projectile smashed suburban Mr Horncastle’s domed glasshouse from such an improbable distance? What is the inner secret of the Reverend Thomas Hampole’s modest little book recounting his rambles in lesser-known London? What draws an eminent nerve specialist to study all this with such deep interest?

Arthur Machen includes within the pages of The Green Round all of the many interests and preoccupations of his writing career. His hero, Hillyer, takes a holiday in West Wales and visits the “Green Round”, a mysterious natural hollow. He soon finds that he has acquired an unwanted shadow, and the novel becomes a study in disclocated parallel realities. With a perceptive new introduction by Machen’s most recent biographer, Mark Valentine.