This is the third Professor Challenger novel, written in 1926, thirteen and fourteen years after “The Lost World” and “The Poison Belt.” In fact, the Professor only plays a small part in it, though reporter Edward Malone once again narrates, and is sometimes accompanied by Challenger’s daughter, Enid. The two are romantically involved. Lord John Roxton also appears. The book is about spiritualism, a strong interest of the author in his later life, and seems to at times be a description of how Doyle was drawn into that interest with near-actual experiences (as described in the end notes), at times something of a tract with lectures to the reader, at times a novel with moments of melodrama and action. How much you might enjoy the book probably depends on how interesting you find the subject. I read a fair amount on it in my early twenties, so I found it worth reading, even if Doyle tends to stack the deck by making the mediums and spiritualists very sympathetic, and those opposed to them nasty and cruel. Probably the most exciting episode is the exploration of a house haunted by a very malevolent presence, which would do any horror writer proud. Challenger himself is on the side of the skeptics, and rejects everything Malone and Enid tell him until the end of the book when he finally agrees to attend a seance that has very surprising results.
In all, I enjoyed the book, though some of the lectures were a slog, and it’s not close to “The Lost World” in quality, though I think it better than “The Poison Belt.” I have two more Challenger short stories to read, written after this, to finish up. By the way, I found this book and the short stories as a free download on Amazon.