I know, “Entities” isn't Joe Nickells newest (it's almost 20 years old, by now), best or most important book. But as I just happened to have lend it from my local library and read it, and it is still available for kindle, I might as well review it. And, I am afraid, the review will not turn out too favorable.
The book argues – as Nickell's mentor Robert A. Baker summarizes in the afterword – that entities like ghosts, spirits, poltergeists, devils, demons, angels, aliens, monsters, and fairies “all are human products”, “produced by the ever-active, image-creating human mind.” Well this is a clear-cut position, worth being argued for, given all the nonsense, myths, and credulity surrounding such purported “entities”. It certainly is a noble pursuit to inject a heavy counterdose of critical thinking and sober information into the discussion. Alas, Nickell's attempt to do so, soon becomes morally dubious, or – to be more precise: – hypocritical.
Let me explain how I come to this rather harsh judgment: I am in no way an “expert” on the subject of poltergeist phenomena, but I have read enough on them – beginning with Gauld/Cornell's classic casebook, over Thurston, Owen, Roll, Rogo, to several eyewitness accounts –, to see that Nickell's handling of the topic is highly inadequate and selective. He tends to ignore or facilely dismiss any evidence that may contradict or impede a naturalistic explanation, while rhetorically conflating all evidence that proves or suggests fraud and illusion, and generalizing from them to the whole phenomenon. It's a blatant case of cherry-picking. And he is using similar strategies throughout the book.
Moreover, the gist of Nickell's argument (and even more so of Robert Baker's in the afterword) seems somewhat circular to me: He argues that there are obviously no such entities like ghosts, poltergeists, demons etc., because invariably all alleged experiences with or evidence for them are just based on delusion, illusion, hallucination, mere belief, fraud or lies. And how does he arrive to this conclusion? Well, as ghosts, demons and suchlike entities do not exist, all the alleged experiences with and evidence for them must obviously be based on delusion, illusion, fraud etc.
If only he would be honest, and state from the onset, that he doesn't believe in ghosts, demons, and all the other purported paranormal “entities” he is writing about, and that he wants to amass all possible evidence and arguments to bolster his belief. Of course, such honesty would prompt the question: “And what about the evidence and arguments for the other side? Shouldn't you first state the best and strongest arguments of the opposite opinion, and then try to refute them and argue for your own?” This, of course, would bring Nickell into serious trouble (and conflate the length of the book considerably).
So, instead of being honest, he chooses another rhetorical strategy: deception. He actually has the nerve to state in his introduction: “let us be neither mindless 'believers' nor close-minded 'debunkers' but instead be investigators who follow the evidence wherever it may lead. In that respect, let us avoid the pitfalls of those who start with the desired answers and then work backward to the facts, selecting only those which fit their preconceived notion and dismissing or rationalizing away the others.” (p. 10) Well, a noble resolution – if only he would heed it! But, as it is, that statement borders on contempt for his readers. For, if you know only a little bit about the subjects he is treating, you will soon realize that he describes exactly his own method, i.e. selecting only those facts which fit his preconceived notion and dismissing or rationalizing away the others; and then he disavows this very same method. Well, this is really – bold!
There is nothing wrong with having a certain belief, conviction or opinion and arguing for it as best as you can. But it is quite another thing to deny one's own bias and to falsely pose as an impartial and evenhanded investigator.
So, what really makes this book so objectionable is – to borrow a phrase from Abraham Lincoln – “the base alloy of hypocrisy”: Professing one thing in the introduction (“follow the evidence wherever it may lead”) and doing the exact opposite thing in the rest of the book (namely cherry-picking and rhetorically distorting the evidence to make it lead where you want it to lead).
P.S.: If you like to read a more balanced approach to “things paranormal”, I would recommend “Randi's Prize” by Robert McLuhan. McLuhan at least tries to see the subject from both sides and to weigh the evidence pro and con. Where, for example, Nickell naively endorses the confession of fraud by the Fox sisters or the somewhat preposterous explanation of a 18th century poltergeist case by Milbourne Christopher, McLuhan exercises some critical thinking and exposes internal contradictions and implausibilities within the “confession” and the “explanation” that cast reasonable doubts on their veracity.