In the typical deep trance, the medium may not have clear recall of all the messages conveyed while in an altered state; such people generally work with an assistant. That person selectively wrote down or otherwise recorded the medium's words. Rarely did the assistant record the responding words of the sitter and other attendants. An example of this kind of relationship can be found in the early 20th century collaboration between the trance medium Mrs. Cecil M. Cook of the William T. Stead Memorial Center in Chicago (a religious body incorporated under the statutes of the State of Illinois) and the journalist Lloyd Kenyon Jones. The latter was a non-medium Spiritualist who transcribed Cook's messages in shorthand. He edited them for publication in book and pamphlet form.
In 1880 the American stage mentalist Washington Irving Bishop published a book revealing how mediums would use secret codes as the trick for their clairvoyant readings. The Seybert Commission was a group of faculty at the University of Pennsylvania who in 1884–1887 exposed fraudulent mediums such as Pierre L. O. A. Keeler and Henry Slade. The Fox sisters confessed to fraud in 1888. Margaret Fox revealed that she and her sister had produced the "spirit" rappings by cracking their toe joints.