This is a factual book about a lady called Alma Fielding. Alma and the haunting of isn't actually that interesting. What is interesting is the beliefs of the time period. Taking place between the two world wars, belief in Spiritualism was widespread because a lot of people had lost men as a result of the first world war.
Eventually the conclusion reached by investigating Alma was : pretty much what happened to her was faked by her, at first unconsciously and then deliberately. That something very traumatic had happened to her in childhood that manifested itself in what looked at first like a poltergeist.
It was found, through studying other alleged paranormal (they called it supernormal) activity that the sufferers had been sexually abused as children and through the fullness of time without any therapeutic services such as counselling etc this manifested itself in so-called hauntings/poltergeists etc. Alma wasn't terribly happy in her marriage and she had lost a baby at 18 months or so. She claimed that she was visited by a male demon and believed it had sexual intercourse with her as she slept (known as an incubus. A succubus is the female equivalent) which, according to research at the time, was a sure sign of childhood sexual abuse (Alma never admitted to this). Alma stopped being investigated when she was told that she had been caught out as fraudulent and not long after this the second world war started and the Institute which was doing the investigating changed beyond all recognition and paranormal investigation pretty much stopped.
This book is very well written and very well researched, as is all Kate Summerscale's books, I just didn't find Alma herself, or what happened to her, terribly interesting. The history of belief in haunting and seances I did find interesting, so I'm glad that I read the book.