Hans Holzer, whose investigations into the paranormal took him to haunted houses and other sites all over the world, wrote more than 140 books on ghosts, the afterlife, witchcraft, extraterrestrial beings, and other phenomena associated with the realm he called "the other side." Among his famous subjects was the Long Island house that inspired The Amityville Horror book and film adaptations. Holzer studied at the University of Vienna, Austria, and at Columbia University, New York, earning a master's degree in comparative religion. He taught parapsychology at the New York Institute of Technology. Holzer died in 2009.