In every culture and for centuries, witnesses report strange encounters with apparitions, or ghosts. Believers point to the mountains of what they consider hard evidence: photographs of ghostly spirits, strange unexplainable voices, and objects flying across the room, as if thrown by unseen hands. But skeptics are just as convinced that there is nothing substantial to this phenomenon, and that belief in ghosts is unfounded. Are these spirits caught between this world and the next, or are they merely figments of wild imaginations?