The Edge of the Unknown Book

For many years, I have read, re-read and thoroughly enjoyed Conan Doyle's stories of Sherlock Holmes. They are well crafted, atmospheric, often puzzling and thoroughly entertaining. I consider many of his mysteries as being the best of that genre ever written.
It's therefore disappointing to have encountered this book, mostly nonsense, purporting to endorse a whole series of supposed supernatural phenomena, all of which could easily have been faked and probably were. Perhaps the most obvious proof that any of the events he describes could easily have been mere illusions is that he starts the book with an account of Houdini's stage antics, tricks that, by Houdini's own admission, did not break any laws that govern the natural world, but were accomplished by his own trickery, secrets he never divulged. Compared to the amazing illusions that Houdini pulled off, the "spiritual manifestations" Doyle describes are child's play.
It becomes apparent that Conan Doyle was quite sincere in his belief in the spiritualist demonstrations had become so popular in his day. He was without doubt an intelligent man, so I can only conclude that he believed this stuff because of an emotional need to do so. Very unfortunate.
The book is a rambling series of references to the activities of a number of the more prominent mediums he observed in action, individuals who were quite notorious at the time but who have now been justly forgotten. The book deserves a similar fate.