Send me a message with the title you want. Mysteries of the Unknown is a series of books about the paranormal, published by Time-Life Books from 1987 through 1991. Each book focused on a different topic, such as ghosts, UFOs, psychic powers and dreams. The idea for the series was conceived following the popularity of the publisher's previous Enchanted World book series. The Mysteries of the Unknown series used scientific aspects for credibility of its theories. The books broke the sales record for the company.