"What sort of magic do you teach, Professor Quirrell?"
"D-Defense Against the D-D-Dark Arts," muttered Professor Quirrell, as though he'd rather not think about it. "N-not that you n-need it, eh, P-P-Potter?" He laughed nervously. "You'll be g-getting all your equipment, I suppose? I've g-got to p-pick up a new b-book on vampires, m-myself." He looked terrified at the very thought.

Harry Potter and the Philosopher's Stone - Chapter 5 : Diagon Alley
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