Unexplained memory usage in iPad iBooks? I have a 16GB Apple iPad 3(with Retina Display). Today, while checking up my available memory, I saw the iPad had about only 1GB left. After deleting major unused apps, I found out that iBooks was using up 1.4GB of storage. I found it to be extremely weird, since iBooks isn't supposed to be consuming so much of space, unless you cram thousands of ebooks in there. 

I have only 4 PDFs and 4 books(purchased from the App Store). Each of these books have about a few hundred (max ~600-700) pages. So, I'm not sure how is the 1.4GB being used up by iBooks.

I'd really like to free up the space iBooks seems to be using. Any help would be appreciated.
A few PDF files of 500 pages with high quality graphics could easily fill up that amount of space. Check how large the PDF files are (easiest way is via iTunes under application data).