For anyone who prefers Apple's own solutions for apps.
iBooks is Apple’s e-bookstore, and as such offers some impressive iPad-specific features. It is also one of the only apps that still supports purchasing a new e-book from within the app using your iTunes account so you can begin reading it immediately (third party booksellers removed this feature when Apple began enforcing the traditional iOS revenue model across all apps). The release of iBooks Author and Apple’s push for electronic textbooks further increased iBooks’ utility, as many of the store’s offerings contain enhanced media and pictures that are optimized for the iPad. The interface is well-designed and easy to use, with options for font size and style, searching, bookmarking, highlights, notes, themes, an in-app dictionary, brightness controls, and the app syncs your purchased books with every device using your Apple ID (although they can only be read on your iPhone or iPad). iBooks also reads books without DRM in ePub and PDF format, though they do not sync across your devices. For those who prefer audiobooks, the VoiceOver feature in the settings app can be used to read books aloud, but be aware that it affects the entire iPad, not just iBooks.
Why we love it
iBooks is free and easy to obtain. It does the basics for ebooks and PDF viewing.