Parapsychology leads us beyond the ordinary limits of the human mind. It challenges classical causality and opens the doors upon a controversial and fascinating world. A world corrupted by superstition and trickery, but rich in spirituality and wonderment. Broadly speaking, psi phenomena may be arranged in three categories:

1. Extra-sensory perception or ESP
Information through channels other than the usual ones provided by ordinary senses. Examples: telepathy, psychometry, dowsing, perception of auras.

2. Psychokinesis
Action-at-a-distance through forces different from the physical ones identified by science. Examples: teleportation, levitation, psychic therapies.

3. Spiritualistic phenomena.
Manifestations of life independent of physical structure. Examples: apparitions, out-of-the-body and near-death experiences, spirit mediumship.

This division is not rigid; any psi phenomena combine various features. Nor is it exhaustive; there are further incomprehensible manifestations. Occult sciences, such as alchemy and witchcraft, claim their share of them.

For the scientific establishment, few cases of psi are worthy of serious investigation. But if we think of it, science already has its hands full with enigmatic manifestations. The creation of a human from a single pair of cells, the metamorphosis of a caterpillar into a butterfly, even the lighting of a simple electric bulb, are not the least of them.