Williams was working on "People of the Black Mountains", an experimental historical novel about people who lived or might have lived around the Black Mountains, his own part of Wales, told through flashbacks featuring an ordinary man in modern times, looking for his grandfather, who has not returned from a hill-walk. He imagines the region as it was and might have been. The story begins in the Paleolithic, and would have come up to modern times, focusing on ordinary people. He had completed it to the Middle Ages by the time he died in 1988. The whole work was prepared for publication by his wife, Joy Williams, then published in two volumes with a postscript briefly describing what the remainder would have been. Almost all the stories were complete in typescript, mostly revised many times by the author. Only "The Comet" was left incomplete and needed small additions for a continuous narrative.