The theme of hysteria and hypnotism has been attracting the attention of medics, psychologists, writers, and the broad lay public. The role of hypnotism in the context of societal functioning, especially in crime, was a subject of research and significant debates between different neurology and psychology schools. One of these debates was between the Nancy and Salpêtrière schools of neurology at the end of the 19th century, and it was focused around a few cases of crime committed allegedly under hypnosis. In order to understand this particular quarrel, this chapter examines the history of mesmerism, hysteria, hypnosis, and fin-de-siècle neurology represented by both the Nancy and Salpêtrière schools.