In this series of lectures delivered in English by the author while visiting the USA, Janet summarises the (at the time) cutting edge perspective on the various forms of hysteria. The syndromes include generalised amnesic states and conversion disorders, and show Janet's highly influential views regarding the fundamental role of dissociation. The lectures provide an insight into the development of this area of psychiatry out of the neurological field of the nineteenth century, with Janet dropping some famous names from the history of medicine.