Athanasius Kircher, a Jesuit priest, produced his vast, encylopedic Mundus Subterraneus in 1664, a compendium of all that was then known about geography and geology, along with discourses on underworld giants, dragons and demons; the spontaneous generation of insects from dung; mining and metallurgy; sections on poisons, astrology, alchemy, fossils, herbs, weather, gravity, the sun and the moon, eclipses, and fireworks—to skim a rock over the surface of the subjects covered. Lavishly illustrated by Kircher himself, it included renderings such as the one here showing his idea of the pockets of interior fire scattered in a network beneath the Earth’s surface. These were probably the first such visual cross sections of the Earth ever done. (Reprinted with permission of the Mineralogisches Institut, Universitaet Wurzburg Am Hubland, Wuerzburg, Germany