Sure, you can read books that are out of copyright on Archive.org or even download the same books and save them to a hard drive or a flash drive. But did you know that you can even borrow current books that are still within copyright?
Books in the Archive.org collection may be borrowed by logged in patrons for a period of two weeks. Internet Archive offers borrowable books in BookReader, PDF and ePub formats. BookReader editions also may be read online immediately in any web browser.
Diane L Richard describes how to borrow newer books from Archive.org in an article in the NGS Blog at: http://upfront.ngsgenealogy.org/2017/10/did-you-know-that-you-can-borrow-books.html