Most library ebooks allow downloading chapters or portions of the ebook as PDFs with no additional software or restrictions. For the example book below (The Calculus Story) access the ebook by clicking on the "Online access may be available" or "Full text available at" links from OneSearch.
*The maximum number of pages that can be printed/downloaded as a PDF varies widely - not all ebooks allow downloading up to 84 pages as a PDF. There are some ebooks that allow very little printing / PDF-downloading, and some that allow hundreds of pages to be downloaded.
Many (but not all) Library ebooks can be downloaded and read offline in their entirety. Some ebooks are simple and only require you to click download to do this. However, there are certain ebooks that are Digital Rights Management (DRM) protected ebooks that limit downloading or require 3rd party software for downloading and offline reading. In most of these cases, the following will be required to download and read a DRM-protected ebook: