It is the initial milestone of the codification of the Spiritist Doctrine, having been the first work to be published by Allan Kardec, on April 18, 1857, dealing with the scientific, philosophical and religious aspects of the doctrine, laying the foundations that would, in the future, be deepened by the Codifier in other works: The Mediums' Book, The Gospel according to Spiritism, Heaven and Hell and Genesis.
Today it contains 1019 questions and answers, duly cataloged and gathered by themes by the Codifier, based on the teachings transmitted by the Spirits and on their observations about the phenomena of the spiritual world. The book, therefore, is the result of a collective work, of real partnership between Heaven and Earth, presenting the principles of the Spiritist Doctrine on the immortality of the soul, the nature of the Spirits and their relations with men, the Moral Laws, the present life, the future life and the future of humanity. As can be seen, it was the first time that spiritual reality, although it has always existed, “appeared in its entirety, thanks to the revelation of the Spirit of Truth promised by Christ”.  In this work, Rivail has already used the name of Allan Kardec, a name he had used in incarnation among the Druids, when he was preparing for the spiritist mission, and not his illustrious baptismal name, Hippolyte Léon Denizard Rivail. The first edition of April 18, 1857 was published with 501 questions and, according to the April 2004 Reformador magazine, its launch took place at Palais Royal, Livraria Dentu, at the Orléans Gallery. The mediums who served this work were initially the young Caroline and Julie Boudin, aged 16 and 14, respectively, to whom Celine Japhet, aged 18 and Miss Ermmance Defaux, aged 14, joined, with the Spirit of São Luiz guided the book review process. After the first draft, the question and answer method was compared with the communications obtained by other French mediums, more than ten according to Kardec, whose psychographed texts helped to structure the work. The second French edition was launched on March 18, 1860, and the Spirits' Book was considered almost as a new work, although there were no alterations to the principles, except for a small number of exceptions, which were considered complementary and clarifications rather than real changes. In order to carry out this review, Kardec maintained contact with spiritist groups from approximately 15 countries in Europe and the Americas, with 1018 questions and answers already in the second edition, with some current issues bringing 1019 questions, an addition that according to the Brazilian Spiritist Federation it stems from the fact that the Encoder did not number the question immediately after 1010, the one that would be 1011. Thus, the book would, in fact, have 1019 questions.  The psychographed responses by the mediums were reviewed, analyzed and often compared to other messages, the revision being necessary because of the difficulty in understanding what the spirits said and, also, because the spirits did not own all the wisdom of the Universe. The final edition consists of four parts. The first deals with the notions of divinity, creation and fundamental elements of the Universe. The second deals with the world of spirits, dealing with the notion of spirit, the purpose of its existence, its potential for self-improvement, its pre and post-existence and also the relationships it establishes with matter. The third deals with moral laws, addressing the Laws of Moral Order of God: worship, work, reproduction, conservation, destruction, society, progress, equality, freedom, justice, love and charity. Finally, the fourth part discusses the hopes and consolations, which include considerations about the future of man, his state after death, the joys and obstacles he finds in the afterlife.
 KARDEC, Allan. The Spirits' Book. Translation by José Herculano Pires. 8th ed. São Paulo: FEESP, 1995. P. 08.  Wikipedia. The Spirits' Book. Available at: <https://bit.ly/2MUvKqQ>. Accessed on: 14 jun. 2018.