"Mysteries of the Unknown" was a highly successful series of books dealing with paranormal subjects which Time-Life Books published from 1987 to 1991. The format and presentation was similar to previous paranormal periodicals published in Britain in the 70s and early 80s, such as the legendary Man, Myth and Magic and the Unexplained magazine:
This irresistible 1988 commercial for the series captures the surreal joy of yesterday's mass market esotericism:
This other spot is less memorable, and probably only notable for an early Julianne Moore appearance:
Mysteries of the Unknown from ODDS AND THENS
The Unexplained from THE TEAROOM OF DESPAIR.