It's been a bit of a Quidditch match this week in bookstores across the English-speaking world as children from 8 to 80 scrambled for their copies of "Harry Potter and the Goblet of Fire," the latest book in the series that has become the biggest publishing phenomenon of the decade.

Did we say decade? Scholastic, Inc., British author J.K. Rowling's lucky American publisher, says the industry has never seen anything like the Harry Potter boom. And did you say you've never heard of Quidditch, the game Harry is so good at? You are obviously a Muggle, a non-publishing-industry grownup or you haven't talked to a child in three years. But then, even some of the inhabitants of Harry's magical realm are at a loss. "I don't really understand Quidditch," says Colin plaintively, somewhere in Book 2 ("Harry Potter and the Chamber of Secrets"). "Is it true there are four balls? And two of them fly round trying to knock people off their brooms?"

Yes, it is. It is also true that there are now four Harry Potter books (out of a projected seven) and all of them are flying round knocking people off the best-seller lists. As with Quidditch, only the initiated really understand it.