A DragonLance d20 System Supplement
From the publishers website:
The wizards of Krynn are granted magic through the power of the three moons. To prevent the awesome powers of wizardry from being wielded by the irresponsible, they require young mages to take a Test proving both their skill and level of responsibility—as well as their level of devotion to magic itself. The Orders of High Sorcery rule over arcane magic and those who practice it from within mighty bastions of power, the Towers of High Sorcery.
This sourcebook contains details of the Towers of High Sorcery. The Towers of Wayreth and Nightlund are explained in great detail, while the "lost" Towers of past ages are presented for the first time anywhere! New prestige classes, spells, magical items, and artifacts are presented—many having been seen only in Dragonlance fiction up until this point. The Test of High Sorcery, an important part of the career of any Dragonlance wizard, is explained in detail, with detailed steps on how to design a Test either as a solo-adventure for the wizard character or a dangerous quest for the entire party!