After a harrowing and dangerous quest, Twilight Sparkle and her friends have recovered Excelsior's Ecstatic Codex from an evil zebra cult intent on ending the world. The Codex, one of the greatest works of dark magic ever forged, carries within its pages a limitless collection of vile, twisted spells, all specially devised for anypony who opens the cover.

What do you do with a book of dark magic? If you're Twilight Sparkle, you put it in your library. Because that's where books go.

After all, books are for everypony.