In this 1917 publication English physicist Sir William Fletcher Barrett (1844-1925) purports to rescue psychical research from the scorn of his colleagues and provide indisputable evidence for the existence of psychic phenomena. A successful scientist (he was elected Fellow of the Royal Society and was honoured with a knighthood), Barrett was better known for his psychical work and his attempts to reconcile it with his scientific pursuits. Certain that the human spirit could linger after bodily death, in this book Barrett examines a wide range of spiritualist practices including levitation, spirit photography, mediumship, automatic writing, the ouija board, clairvoyance, and telepathy, carefully considering the evidence for each phenomenon in the hope that they will in time be recognised as scientifically established facts. This book is a much-revised edition of Barrett's 1908 publication On the Threshold of a New World of Thought, republished to include more 'trustworthy' evidence.