If you read ebooks, either on a Kindle or an iPad, here's an article that might be helpful. http://www.nytimes.com/2016/02/24/technology/personaltech/loading-the-kindle-library-on-an-ipad.html?smprod=nytcore-ipad&smid=nytcore-ipad-share
If you have purchased books on an Amazon Kindle e-reader, you can download the collection onto your iPad with the iOS Kindle app.
Jim Hamm