The Spirits' Book constitutes the most excellent repository of teachings on the existence and nature of spirits and their relations with the world, to this day it's considered as the landmark of Spiritism. From it comes the explanation of all the apparent anomalies of human life, of all intellectual, moral, and social inequalities, enabling man to know where he comes from and where he goes. In 1857, the manuscript was ready and, although the book was born under the sign of controversy, and already has others that were on this subject, it was released on April 18 and was a success.The Book reached a large number of readers of all classes, a surprising success in France, the rest of Europe and repercussions for the Americas, and the name Kardec became familiar. It's a brilliant answer to the great enigmas of the Universe, its division organized in a gradual sequence of knowledge, presented in didactics, leads the reader to the world of logic where every inhabitant recognizes and agrees with the proposed scientific and philosophical models. The publication made a sensation, it had communications from the spirits who answered his questions related to all subjects, from the internal structure of matter to the nature of God, human ethics, the Universe and the place of Humanity within it.