Fantasy settings are defined by their magic . . . so different worlds need different magic systems. GURPS Thaumatology has GURPS Fourth Edition updates of the best Third Edition magic variants, plus many all-new options. This mighty tome includes: * Minor tweaks for the spell-based magic of the Basic Set: restructuring prerequisites and colleges, modifying Magery and mana, new magical energy sources, adapting spells on the fly, and more. * Radical revisions of spell-based magic, including detailed versions of the clerical and ritual magic options hinted at in the Basic Set, and the return of that Third Edition classic, "unlimited mana." * Traditional alternatives to spells, such as ceremonial, spirit-mediated, and runic magic. * World-shaking freeform magic. * Magic as inherent powers. * An in-depth look at material magic, with new alchemy, herbalism, and enchantment options; rules for free-willed items and magical gadgets; and guidelines for "the stuff of raw magic." * Notes on adapting real-world occult concepts – such as the Laws of Magic, astrology, and traditional material components – to any magic system. * Guidelines for running magic-oriented games, advice on combining magic systems, and detailed outlines for four distinctly different fantastic campaigns.