Chauncy Hare Townshend (1798–1868), poet and collector, was a well-connected friend of Robert Southey and Charles Dickens. He became fascinated with Mesmerism while in Germany and went on to popularise it in England. This book, first published in 1840, was his passionate defence of Mesmerism. Developed in the late eighteenth century by Franz Mesmer, Mesmerism was a kind of hypnosis based on the theory of animal magnetism. With its spiritual associations and uncanny effects, it was an extremely controversial topic in the nineteenth century and its practitioners were widely considered fraudsters. Townshend describes in detail the mental states Mesmerism induces, which he identifies as similar to a state of sleepwalking. Perhaps most fascinating are the eye-witness accounts describing experiments carried out by Townshend on the continent, in which he hypnotised his subjects into feeling his own sensations and knowing things they could not know.