Epic Level Handbook by Wizards of the Coast

A rules supplement for taking characters beyond standard level caps, offering mechanics for epic-level advancement, new feats, prestige classes, spells, and monsters, plus guidance on crafting and balancing legendary magic items and challenges; it provides systems for experience progression, epic combat and skill use, divine interactions and improvising high-power encounters so referees can run campaigns where characters wield world-shaping abilities without breaking game balance.