From publisher blurb:
Elements of Magic — Mythic Earth gives you the rules to create magic as it is seen in the myths that are alive in every setting, ancient or modern. Mythic Earth presents rules compatible with both Fantasy d20 and Modern d20, and is an update of the flexible spell creation system of Elements of Magic. Additionally, whether you want to explore the myths of the real world, or you want to play in a fantasy world of your own creation, this book will help you understand the role myths play in history and society, and will aid you in composing adventures with mythic resonance.
Mythic Earth will help you bring the grandeur of myths and the intricacies of superstition and folklore to life in your games. From street magicians and voodoo priests to Chinese sorcerers and the various stripes of witches, all the magical beliefs of humanity and the infinite worlds of fantasy are yours to wield as you explore the mysteries of Mythic Earth.
Over twenty magical traditions are presented, drawn from the magical beliefs of our own world, though other traditions are easily possible for other worlds. Each magical traditions has some types of magic it is good or bad at, so Christian miracle workers are more likely to be skilled at healing, and Aztec blood mages will be most adept at attack spells. Characters of any class can learn magic, though only those who devote themselves to it will become truly powerful.