Books like the upcoming Harry Potter become bestsellers long before they even hit stores. “The growth of pre-sales is an interesting development in publishing. Of course in the eighteenth century an author could pre-sell his book by subscription as a way of supporting himself, but this is a different kettle of fish. Publishers love it because it lets them lock in sales without having to worry about returns. With enough hype or a strong enough brand name the whole enterprise can turn into a form of print-on-demand. It’s quite a testimony to the importance of marketing.”