Thomas Metzinger had his first out-of-body experience when he was nineteen. He was on a ten-week meditation retreat in the Westerwald, a mountainous area near his home, in Frankfurt. After a long day of yoga and meditation, he had a slice of cake and fell asleep. Then he awoke, feeling an itch on his back. He tried to scratch it, but couldn’t—his arm seemed paralyzed. He tried to force the arm to move, and, somehow, this shifted him up and out of his body, so that he seemed to be floating above himself. Gazing out into the room, he was both amazed and afraid. He heard someone else breathing and, in a panic, looked around for an intruder. Only much later did he realize that the breathing had been his.