Influential French philosopher (1859–1941) who was strongly interested in psi phenomena, from which he developed a ‘filter’ theory of consciousness. 

Annie Besant (1847–1933) was an English theosophist, socialist and women’s rights activist with an interest in psychical research for the purpose of spiritual development.

Theodore Besterman (1904-1976) was an author, translator and psychical researcher, who investigated mediums and wrote books and articles on paranormal topics.

Dutch psychologist and parapsychologist, with a background in molecular physics. His experimental psi research has included work on ESP and presentiment effects. He has also experimented on the role of consciousness in quantum collapse.

Malcolm Bird (1886–1964) was an American mathematician and parapsychologist, notable for his involvement in controversial investigations of the Boston medium Mina Crandon.

British psychologist, consciousness researcher and psi sceptic, who has frequently appeared in the media promoting a non-paranormal view of out-of-body and near-death experiences.

English architect and archeologist  (1864–1945) remembered for claims that archeological discoveries at Glastonbury Abbey were achieved through contacts with deceased monks.

Psi researcher based in Arizona, co-founder of the Windbridge Institute and Windbridge Research Center.

This English writer and editor (1880-1961), notable for her role as amanuensis for Henry James, was an active SPR member and practised automatic writing.

Italian psychologist and psychical researcher (1862–1943), author of number of books analysing psi phenomena.