The Book on Mediums

The Book on Mediums, published by Allan Kardec in 1861, is the second of the five Fundamental Works of Spiritism. Where its predecessor set out the philosophy, this volume concentrates on the experimental and investigative side of the doctrine. It was meant as a practical handbook for would-be mediums, offering theory and basic methods for examining the interaction between the physical and spiritual worlds.

The book is notable for its focus on theory rather than practice. It gives almost no ritual, since Kardec considered ceremonies superfluous, and devotes its pages to classifying paranormal phenomena, especially those able to convey messages, and to describing the mechanisms that Spiritism held to be involved. It opens by defending the existence of spirits on empirical and logical grounds, distinguishes the extraordinary from the supernatural, and warns against the fanatical, charlatanic and polytheistic tendencies that had appeared among followers.

The work describes phenomena such as table-turning, apparitions, psychography and telekinesis, and offers advice on handling communications: do not accept a spirit's claimed identity without evidence, judge spirits by the morality they express rather than by their names or the medium's culture, and never let spirit advice govern one's life. Its final chapters present the statutes of the Spiritist Society of Paris, offered as a model for other societies.