The New York Times reports how libraries are lending e-books:

Most digital books in libraries are treated like printed ones: only one borrower can check out an e-book at a time, and for popular titles, patrons must wait in line just as they do for physical books. After two to three weeks, the e-book automatically expires from a reader’s account.

But some publishers worry that the convenience of borrowing books electronically could ultimately cut into sales of print editions.