Dem's book was part of the flood of Ancient Astronaut books inspired by the huge success of Erich von Daniken's Chariots of the Gods?
Ancient Astronaut books are about Mayan conspiracies. 
mnli hypothesis: Ancient Astronaut books are about Mayan conspiracies.  premise: Dem's book was part of the flood of Ancient Astronaut books inspired by the huge success of Erich von Daniken's Chariots of the Gods?