The format of NC Digital Library has changed, here are instruction pages for downloading. More information can be found under the “How To” tab at the top of the page.
For Kindle users (does not include Kindle Fire): Kindle
For Tablets such as iPad, Android, Kindle Fire, Nook Color,etc: Tablets
For eReaders such as Nook, Sony, and other non-Kindle devices: Nook-Sony-etc