“The very power of [textbook writers] depends on the fact that they are dealing with a boy: a boy who thinks he is ‘doing’ his ‘English prep’ and has no notion that ethics, theology, and politics are all at stake. It is not a theory they put into his mind, but an assumption, which ten years hence, its origin forgotten and its presence unconscious, will condition him to take one side in a controversy which he has never recognized as a controversy at all.”