Controlled Digital Lending Fact Sheet | Controlled Digital Lending by Libraries

"CDL is the digital equivalent of traditional library lending. A library can digitize a book it owns and lend out a secured digital version to one user at a time, in place of the physical item.

CDL has three core principles:

1. A library must own a legal copy of the physical book, by purchase or gift.
2. The library must maintain an "owned to loaned" ratio, simultaneously lending no more copies than it legally owns.
3. The library must use technical measures to ensure that the digital file cannot be copied or redistributed.

Beyond these core principles, libraries may choose to implement CDL in different ways. ..."