That Hideous Strength

That Hideous Strength: A Modern Fairy-Tale for Grown-Ups is a novel by the English writer C. S. Lewis, published in 1945. It is the final book of his theological science fiction Space Trilogy, and it also appeared in an abridged form under the title The Tortured Planet.

Its events follow those of Out of the Silent Planet and Perelandra and feature the philologist Elwin Ransom once again, but unlike the first two books the story takes place on Earth rather than elsewhere in the Solar System. At the centre of it is an ostensibly scientific body, the National Institute for Co-ordinated Experiments, which turns out to be a front for sinister supernatural forces.

The novel was written during the last period of the Second World War and is set in an undetermined year after the end of it. Mark Studdock is a young academic who has just become a senior fellow in sociology at Bracton College in the University of Edgestow, where the fellows are debating the sale of a portion of college land to the Institute. The sale is controversial, because the land in question, Bragdon Wood, is an ancient woodland believed to be the resting place of Merlin. Once the deal is struck, an Institute insider named Lord Feverstone proposes that there may be a post at the Institute for Mark.

Mark's wife Jane, a doctoral student at the university, has been suffering from a peculiar nightmare involving a severed head. She meets Mrs Dimble, the wife of one of her former tutors, who is being evicted because of the sale of the land, and Mrs Dimble sends her to seek counsel from a Miss Ironwood at the Manor in the nearby town of St Anne's. In his foreword, Lewis says that the point of the novel is the same as that of his non-fiction book The Abolition of Man, which argues that there are natural laws and objective values that education should teach children to recognise, and the title comes from a poem of 1555 by David Lyndsay, in which the phrase describes the Tower of Babel.