One May morning in 1952, Aldous Huxley saw his trousers properly for the first time: ‘Those folds in the trousers – what a labyrinth of endlessly significant complexity! And the texture of the grey flannel – how rich, how deeply, mysteriously sumptuous!’ Spellbound, his vision transfigured by an extract of the Mexican peyote cactus, he added, ‘this is how one ought to see.’ It is a famous, even infamous, moment. What is not so famous is the fact that Huxley wasn’t actually wearing grey flannels. He was wearing blue jeans, but his wife, Maria, made him change them to flannels when he wrote about the experience in The Doors of Perception (‘she thought I ought to be better dressed for my readers’). As Mike Jay says in Mescaline, it was an inspired suggestion: ‘The image of Huxley on a psychedelic voyage in his grey flannels captured precisely the book’s winning sense of intellectual gravitas surprised by joy.’

The breadth of information and cultural nous are characteristic of Jay’s excellent book, which itself combines joy and gravitas and adds up to a comprehensive history of a still-enigmatic substance. Mescaline may have been elbowed aside in recent decades by LSD and a galaxy of other hallucinogenic substances that have