It ran to 156 issues, with issue 157 being an index to the collection, and dealt with the paranormal and mysteries such as UFOs, the Bermuda Triangle, ghosts, spontaneous human combustion, the Cottingley Fairies, ancient knowledge, sea monsters, the Yeti, weird coincidences, stone circles, contact with the dead, and notable historical characters linked to the occult.
[1][2] The magazine was edited by Peter Brookesmith, and consultants included Dr. J. Allen Hynek and Professor A. J. Ellison.
The editorial director was Brian Innes,[citation needed] who had previously worked on Man, Myth & Magic: An Illustrated Encyclopedia of the Supernatural.
A complementary version was published in France, entitled L'Inexpliqué, which contained differently written articles.
[citation needed] The partwork, which debuted on newsstands the same year the British TV series Arthur C. Clarke's Mysterious World (1980) was first broadcast, was hugely popular.