Sir William Fletcher Barrett (February 10, 1844 - May 26, 1925) was Professor of Physics at the Royal College of Science for Dublin from 1873-1910 and one of the distinguished early psychical researchers. He was instrumental in the founding of the Society for Psychical Research (SPR) in 1882, serving as vice-president and editor of the Society's Journal during its first year and he became president in 1904. He also encouraged Professor William James of Harvard to organize the American branch of the SPR. in 1884. First published in 1917, On the Threshold of the Unseen is Barrett's examination of spiritualism, psychic phenomena, and life after death. Topics covered include, science and scepticism, automatic writing, clairvoyance, telepathy, direct voice, spirit photography, and much more. During his 50 years of psychical research, Barrett observed many types of psychic phenomena. Recalling his past experiences at a private meeting of the SPR on June 17, 1924, less than a year before his death, Barrett said: "I am personally convinced that the evidence we have published decidedly demonstrates, the existence of a spiritual world, survival after death, and of occasional communication from those who have passed over... It is however hardly possible to convey to others who have not had a similar experience an adequate idea of the strength and cumulative force of the evidence that has compelled [my] belief." Almost a century later, On the Threshold of the Unseen is still considered essential reading of anyone interested in psychical research and survival of consciousness after physical death.