“And just look at these books!” said Hermione excitedly, running a finger along the spines of the large leather-bound tomes. “A Compendium of Common Curses and Their Counter-Actions . . . The Dark Arts Outsmarted . . . Self-Defensive Spellwork . . . wow . . .” She looked around at Harry, her face glowing, and he saw that the presence of hundreds of books had finally convinced Hermione that what they were doing was right.
— J.K. Rowling, Harry Potter and the Order of the Phoenix