Allan Kardec was the pen name of Hippolyte Leon Denizard Rivail, a French teacher and author of school textbooks who had studied under the educational reformer Pestalozzi. He was in his fifties and rationalist by temperament when in 1854 he was persuaded to look at the table-turning craze then sweeping Paris. He concluded that something was happening and set out to investigate it as a subject rather than a diversion.
His method was a questionnaire. He put more than a thousand ordered questions to a number of mediums working separately, and treated as reliable only those answers that agreed across independent sources, a procedure he called the control of universal teaching. The result was The Spirits Book in 1857, which remains the foundational text.
Four more books completed the system: The Mediums Book (1861) on practice, The Gospel According to Spiritism (1864) on ethics, Heaven and Hell (1865) and Genesis (1868). Together they are known as the codification.
The doctrine holds that God is one, and that spirits are created simple and ignorant and progress through many successive lives, always forward and never into animal bodies. There is no eternal damnation and no hell as a place; suffering is the natural consequence of one's own state and is corrective. The spirit is joined to the body through an intermediate envelope, the perispirit. Other inhabited worlds exist at differing stages of moral advancement.
There is no clergy, no sacrament, no ritual and no payment. Mediumship must be exercised free of charge, and Spiritist centres run on study, unpaid mediumistic sessions and charitable work. Kardec insisted that Spiritism was a science and a philosophy with moral consequences rather than a church, and its institutions still make that claim.