Book of Lost Spells
Ask any wizard. There's no such thing as too many spells. This massive compendium of magical mayhem ought to satisfy even the most discerning necromancers and thaumaturgists, and they aren't easy to please (especially the necromancers).
Containing hundreds of new spells, the Book of Lost Spells is a vital resources for anyone wanting to add a bit more mystery to the magic of the Pathfinder RPG or Fifth Edition!
Note: The Fifth Edition version has a blue border while the Pathfinder Roleplaying Game version has a red border.