Theo Clare

Theo Clare is the pen name British crime novelist Mo Hayder (1962-2021) used for The Book of Sand (2022), a speculative thriller she completed shortly before her death from motor neurone disease. Where Hayder's crime fiction as herself -- the Jack Caffery series and four standalone thrillers -- is forensically grounded and set in the recognisable present, The Book of Sand follows a mother's search for her missing daughter into a strange, shifting desert landscape that reads closer to dream-logic fantasy or magical realism than to a police procedural, which is presumably why it was given a separate identity rather than published as a Mo Hayder novel.

Some early listings for The Book of Sand describe it as the opening volume of a planned sequence, suggesting Hayder may have intended to return to the name and the story for further books. That never happened: no further book appeared under the Theo Clare name, and it remains a single, complete work published posthumously in 2022, a year after its author's death, standing as her last piece of fiction to reach print and a final, unexpected turn away from the crime genre that had defined her career.