The Spirits' Book, Kardec states: - "It was written by order and following the dictation of Superior Spirits, to establish the foundations of a rational philosophy, free from the prejudices of the system spirit. It contains nothing that is not the expression of their thoughts and that has not been examined by them.

Only the order and methodical distribution of the material, as well as the notes and the form of some parts of the writing, constitute the work of the one who received the mission of publishing them." In this third edition of the book, Cosme Massi proposes a didactic order for the chapters of this book by Kardec and analyzes his Introduction to the study of the Spiritist Doctrine.

The book tries to explain the order of the four parts and their respective chapters. Some diagrams and arguments are presented that justify the order proposed in The Spirits' Book, the main one in Spiritism; it is from this that all the other works of Allan Kardec were written.