Copyright law is intellectual property law. It's the only kind explicitly mentioned in the US Constitution. Regular copyright law says that if you _buy_ a book

Copyright law is intellectual property law. It's the only kind explicitly mentioned in the US Constitution. Regular copyright law says that if you _buy_ a book, digital or not, you can resell it. If you license a book, digital or not, you can't except as specified in the license. IA's point is that digital books (which are many or most books nowadats) aren't sold; instead, they are licensed. https://www.justice.gov/archives/jm/criminal-resource-manual-1854-copyright-infringement-first-sale-doctrine https://www.justice.gov/archives/jm/criminal-resource-manual... > Further, the privileges created by the first sale principle do not "extend to any person who has acquired possession of the copy or phonorecord from the copyright owner, by rental, lease, loan, or otherwise, without acquiring ownership of it." See 17 U.S.C. § 109(d).