Leonora Piper (1857 – 1950) was a famous American trance medium in the area of Spiritualism. Piper was the subject of intense interest and investigation by American and British psychic research associations during the early 20th century, most notably William James and the Society for Psychical Research.

In 1885, the year after the death of his young son, the psychologist and SPR member William James had his first sitting with Piper at the suggestion of his mother-in-law.. He later wrote: "My impression after this first visit was that Mrs. Piper was either possessed of supernormal powers or knew the members of my wife's family by sight and had by some lucky coincidence become acquainted with such a multitude of their domestic circumstances as to produce the startling impression which she did. My later knowledge of her sittings and personal acquaintance with her has led me to absolutely reject the latter explanation, and to believe that she has supernormal powers."

Piper's talent was considered to be so extraordinary that she was taken to England for 83 sittings for men considered to be the premiere psychical researchers of the day, including Henry Sidgwick, Sir Oliver Lodge, Sir William Barrett and F.W.H. Meyers. Although she was in a place where she had never been before, was closely watched, Piper did extremely well and continued to amaze even the most hardened investigators. Hodgson published a cautious report of his work with Piper in 1892 but in 1898, he revised slightly this and accepted her as genuine.

Leonora Piper died on July 3, 1950 and has since come to be regarded as a medium of the first rank. She gave much of her life in the service of science and as a result, many who had previously doubted the possibility of survival after death became convinced of its reality. One of those, of course, was Professor William James, whose words about Leonora Piper have long survived his own passage from this world:

"If you wish to upset the law that all crows are black, it is enough if you prove that one crow is white. My white crow is Mrs. Piper."[1]

[1]Murphy, Gardner; Ballou, Robert O. (1960). William James on Psychical Research. Viking Press. p. 41