This is a very rare book, of which only 25 copies are known to exist. It is the first one exposing correctly the methods used by the fake mediums and apparently the mediums themselves bought most of them and burnt them out. A modern reprint exists. The book isn't in good conditions, due to the pulp paper used for it, and is not recommended as a reading copy.
A second edition of this book, more widely available, has been published in the UK in 1922 by Harry Price and Eric J. Dingwall as a facsimile edition