The Book of Magecraft (AD&D/Birthright)

Magic permeates the very air, earth, and sea of Cerilia -- yet escapes the mastery of all but a rare few. Those who control the continent's magical energy can call upon forces incomprehensible to the rest of its inhabitants. These powerful figures are Cerilia's wizards: adventurers, advisers, and kings whose spells can affect the destinies of thousands.