Men Among Mankind the culmination of Trench's research into the nature of UFOs., and according Trench - UFOs, turn out to be the hidden technology of the remaining Atlantians who survived the cataclysm which was possibly the destruction of the 5th planet creating the asteroid belt and a lot of solar system debris. After the cataclysm the Atlantians moved into the cities and been walking among us for all these centuries guiding us spiritually and technologically into the future.