Europe has ruled (PDF) that e-books can be lent out just like their physical counterparts. That is, as noticed by Ars Technica, one copy can be "checked out" by one person at a time. After the lending period expires, that user can no longer use the book and it goes to the next person who wants it. This might sound kind of expected, but you have to remember that it took until 2014 for the European Union to approve digitizing library books in the first place. And even then, you could only use them within the library's walls and at dedicated terminals.