At issue in Kirtsaeng v. John Wiley & Sons is the first-sale doctrine in copyright law, which allows you to buy and then sell things like electronics, books, artwork and furniture, as well as CDs and DVDs, without getting permission from the copyright holder of those products. Under the doctrine, which the Supreme Court has recognized since 1908, you can resell your stuff without worry because the copyright holder only had control over the first sale.