answer:If a book you’re looking for is published under a restrictive license and/or bundled with a DRM scheme, there will not be any legal way for you to get it without. That’s not to say there aren’t ways, but ones that we can’t talk about on this site because they are illegal. You already know about gutenberg.org, which is probably the best and most extensive such library available. If you would specify what sort of books you are looking for, then we might be able to help you find such titles free and legally- for example, Baen Books has a pretty large selection of DRM-free science-fiction titles.