3. IBooks

On iTunes at itunes.apple.com
Free
Apple have designed their very own app for book lovers: iBooks. Apple is constantly updating iBooks to reflect user feedback, which makes it one of the best functioning book apps on the iTunes store. The app itself is optimized to work best with the iPhone 5 or later releases, but still works well for a general reading app on older iPhones. Features include smooth page transitions, which make full-use of the new retina screen, as well as a good user interface and simple design.