Trevor H. Hall

In his controversial book The Spiritualists (1962), Hall stated that the famous medium Florence Cook was a fraud who had an affair with the chemist and psychical researcher William Crookes.

[8] Regarding Hall's research that Cook had an affair with Crookes, historian Asa Briggs in a review commented that "the verdict does not seem to be fully proven, although the evidence is striking".

[9] Psychologist Ray Hyman has noted that despite how one may consider the allegations, "there is no question that Hall has unearthed much material that throws strong suspicions on Crookes's handling of this investigation.

[19] Researcher Georgess McHargue noted that Hall was "one of the most astute of modern investigators, combining twentieth-century scientific techniques with a cheerful and readable writing style in his many books.

"[20] However, Roger Luckhurst has written that Hall's "books proceed with a combination of careful archival work and abusive character assassinations.

"[21] In the book A Skeptic's Handbook of Parapsychology (1985), authors Gerd H. Hövelmann, Marcello Truzzi and Piet Hein Hoebens noted that "[al]though Hall's historical detective work is often impressive, his conclusions sometimes go beyond his data.