In it, he examined the areas of telepathy, clairvoyance, precognition, and psychokinesis and analysed many major ESP experiments that claimed to have conclusively demonstrated the phenomenon.

[7] He suspected that the data from the Soal-Goldney experiments, run by Samuel Soal, was fraudulent but parapsychologists refused to accept Hansel's charge.

[11][12] In his revised edition, Hansel (1980) points out that "after 100 years of research, not a single individual has been found who can demonstrate ESP to the satisfaction of independent investigators.

[15] The physicist Victor J. Stenger noted that "Hansel succeeded brilliantly in exposing the shoddiness of the experimental procedures of Rhine's laboratory.

[21] The psychologist David Marks in his book The Psychology of the Psychic (2000) noted that his discovery of an experimental error in parapsychological experiments confirmed the research of Hansel.