The Mediums' Book sees Allan Kardec introduce and explain how human beings can communicate with the vast spiritual realm. Through this book, we learn how to make contact with spirits of humans and ancestors, and identify both good and evil spirits. An excellent book of spiritual guidance, Kardec explains the methods of mediumship. How a seeker of the spirits can build an understanding of the practices needed to summon, and how the rituals must be carried out, is covered in many detailed chapters. Kardec is honest about the pitfalls; upsetting the spirits, or incurring the wrath and misfortune unleashed by malevolent spirits, is something a medium must always be cautious of. In studying the behavior of the spirits, Kardec answers questions about whether they attach themselves to people or objects. We discover why spirits can manifest even without the presence of a learned medium; such as in haunted houses or other sites.