“We shall not use the word ‘sí,’” he told his students in their first lecture. “We shall not refer to them as síogaí or (God forbid!) fairies. For the sake of politeness (and our own safety) we shall use the terms Na Daoine Maithe or Na Daoine Uaisle.* For, as we shall see, when dealing with these gentlemen we must at all times be seen to be respectful. Or else.”