For many millenia and across the whole Old World, from Eastern to Western Eurasia, and fro the tip of Southern Africa to the highlands of Britannia, people were in the habit of practicing divination, or the art of translating information from their gods into the realm of human knowledge. On a scale whose breadth we have yet to fully appreciate, they assumed clandestine signs were continuously being revealed through the natural world and its creatures (including their own bodies, asleep or awake). They received messages from temple-based oracles, as well as in their dreams, from the entrails of the animals they killed, from lightning, fire, lots, pebbles, livers, fired tortoise shells, the stars, birds, the wind, and nearly anything else that moved.1 These practices were not, for the most part, considered esoteric or marginal. The inclinations of the divine, like the weather, were simply a part of the ancient atmosphere, and just about wherever we look in the sources, we find people trying to gauge the prevailing winds. Scholars have yet to take account of the extraordinary diffusion of the phenomenon. It belongs to a small group of rather widely shared cultural forms from antiquity, alongside things like myth or sacrifice. While surely there is no easy, global answer as to why this is the case, better local answers will emerge from a fuller reckoning with this fact of near universal diffusion.