Historical psychical research covers many topics but it is a fact that the careful and prolonged studies by psychical researchers, sometimes over decades, of mediums such as Mrs Piper, Mrs Leonard, Mrs Willett, Mrs Garrett and Miss Cummins have demonstrated beyond any reasonable doubt to anyone of open mind that these psychics again and again could acquire knowledge in a paranormal manner. The majority of the psychical researchers who participated in such studies or who came later into psychical research and studied carefully the detailed, thoughtful, numerous and varied case reports in the literature, concluded that unless one accepted a variation of super-telepathy and clairvoyance, the possibility that some human beings survive death, retaining their essential personalities, memory, characteristics, skills, and concern for those they have left behind, had to be taken very seriously indeed.