The year is 1793 and Herbert Powyss is set on making his name as a scientist. Determined to study the effects of prolonged solitude on another human being, he advertises for someone willing to live in his cellar for seven years in return for a generous financial reward. The only man to apply is John Warlow, a semi-literate farm labourer with a wife and six children to support. Cut off from nature, Warlow soon begins losing his grip on sanity while, above ground, Powyss rapidly becomes obsessed with Warlow's wife, Hannah.The experiment, a classic Enlightenment exercise gone more than a little mad, will have unforeseen consequences for all included. In this seductive tale of self-delusion and obsession, Alix Nathan has created an utterly transporting historical novel which is both elegant and unforgettably sinister.A Sunday Times fiction book of the year'She is an original, with a virtuoso touch' - Hilary Mantel'An extraordinary, quite brilliant book' - C. J. Sansom'A powerful and unsettling novel' - Andrew Taylor Featured on Radio Four's Book at BedtimeBBC History Magazine Best Historical Fiction of 2019