From publisher blurb:
Uncover Forgotten Arcane Lore!
Everyone knows that knowledge is power, and that having options is better than not having them. It should come as no surprise, then, that wizards, witches, and other powerful spellcasters are always on the lookout for new and exciting spells to add to their repertoires. While many spells from the Pathfinder Roleplaying Game Core Rulebook received a facelift and an upgrade in Mythic Adventures, the sourcebook that introduced mythic power to the game of Pathfinder, dozens of spells were left behind. Missing Mythic Magic Volume I, and its successors, aim to give each and every spell from the core rules a full-fledged mythic upgrade, all the way from A to Z, with a special focus on making mythic spells that feel as over-the-top and larger-than-life as possible.