An upcoming Supreme Court case, Kirtsaeng v. John Wiley & Sons, involves an eBay seller who was sued by a textbook publisher for reselling books.

The seller, a graduate student and entrepreneurial seller, sold the books to help cover tuition expenses. These were legitimate books that the book publisher manufactured overseas — they were not counterfeit, pirated, or stolen. Yet, the publisher is trying to use U.S. copyright law to stop the book sales and make the seller pay $600,000...