Parapsychology is the scientific study of unusual human experiences like telepathy, precognition, and psychokinesis. It does not include areas like astrology or searching for cryptids. Parapsychologists study phenomena like ESP, psychokinesis, near-death experiences, and reincarnation. Physicists, biologists, psychologists, and philosophers are interested in parapsychology because it challenges assumptions about perception, energy, and the mind-body problem.