To find books (and more!) use DePauw's Discovery search.
The screencast below describes how to limit to e-books in WorldCat Discovery.
If you're taking classes and/or living on campus, you can request books be pulled for you, via our contactless pickup system.
NOTE: there is no interlibrary loan (ILL) of books available in Fall 2020, whether you're on or off-campus.
The Internet Archive has access to digitized copies of a lot of books, similar to Google Books. What's different is that there's usually full-read capability (not getting cut off after a few pages, like in Google Books). HOWEVER, any book in there can only be used by one person (in the world) at a time. Sometimes they have digitized more than one copy of a book, though. You can search/browse without an account, but to read a whole book, you must create a free account. Then you can check out a book (for one hour or two weeks - lots of variables) to read. Definitely not a perfect solution, but in this imperfect moment in time, it's helping some people get what they need!
Google Books allows you to search a wide variety of digitized books. Many will let you see a preview of the book, and if out of copyright, perhaps the entire work. You can search the text of books to see where key terms appear. However, you can't download - it's all "read online" access, and often you get cut off right when you get to the page you need in the preview.