Influential Italian criminologist, doctor and psychiatrist (1835-1909) who engaged in psychical research and endorsed the Italian medium Eusapia Palladino. 

German physicist who has developed a theory of psi based on quantum mechanics.  

Psychologist and psi researcher focusing in particular on the effects of psychoactive substances.

British playwright and social activist (1865-1948) who became involved with psychical research and practised automatic writing

Brazilian psychologist with a special interest in poltergeist phenomena and the psychological and psychosocial implications for experiencers of psychic phenomena.

New Zealand-born journalist and novelist (1911–2001) who also wrote and reviewed books about psychical research.

Wealthy landowner and philanthropist (1873-1913) who became Mexico's 37^th president and whose career was profoundly influenced by his mediumship activities and spritist beliefs.

German psychologist whose work in consciousness theory has extended to include experiments in psychokinesis and precognition.

Brazilian psychologist with research interests in the psychology of non-ordinary experiences, spirituality, religion and health.

Fench existentialist Roman Catholic philosopher (1889-1973) who as a young man was actively involved in psi research in France, and speculated on the ways in which psi might operate.