The moment that many die-hard Harry Potter fans have been waiting for arrived yesterday, just a few days before Christmas. The sixth installment in J.K. Rowling's madly popular series, Harry Potter and the Half-Blood Prince, will be available July 16, 2005. Get ready for the fanfare and the Potter parties this summer.

This is, of course, preemptive good news for booksellers such as Barnes & Noble (NYSE:BKS), Borders Group (NYSE:BGP), and Books-A-Million (NASDAQ:BAMM). It's also good news for Motley Fool Stock Advisor pick Amazon.com (NASDAQ:AMZN). All of these merchants are allowing excited fans to preorder copies. It stands to reason that scads of folks will be getting Harry Potter IOUs in their stockings this year.

Of course, the news is best of all for Scholastic (NASDAQ:SCHL), which is the publisher of the Harry Potter books. Anyone who's been following the publisher's fortunes knows that it tends to get most exciting when there's a brand new Harry Potter book on the shelves.

While Harry Potter is a great gift for Scholastic shareholders, there's also the small problem that Scholastic has had its share of troubles during Harry Potter down times. And over the long term, investors should likely be worried about a stock that hangs so much store by a franchise that will, eventually, come to an end -- or worse, just get old in the meantime.

I'm sure that any suggestion of such a thing will cause a fair amount of indignation among Harry Potter loyalists, and of course I'd say there are better chances that the franchise will continue to perform strong through the finish, given its history thus far. (Although the fifth book definitely had the added titillation that a major character was going to meet his demise.) Regardless, Harry Potter has been an incredibly popular phenomenon with vast staying power.

It seems to me, though, that Scholastic would be more appealing as an investment if it's able to boost the fortunes of some of its other lines, as was suggested here. Those who have invested in the booksellers named above will welcome the summer treat, as will Scholastic, and I know many of us will welcome the long-awaited return of the magic of Hogwarts this summer. However, it's not hard to think of Scholastic as a one-trick pony and ask the question: What happens when Harry grows up?

Meet the ghosts of Harry Potter past:

Members of the Fool community are already buzzing about yesterday's development on our own Sirius Black's Muggle Friends discussion board.

Alyce Lomax does not own shares of any of the companies mentioned, but she has read all the Harry Potter books thus far.