Requirement of the iPad app is to display an ebook that allows user to edit and save it. Further requirements are like navigation and bookmarks. In precise, just similar to the iBooks app.
My question is, is it possible to edit the .epub file? I believe we can edit .pdf files (As I have seen some apps available on iTunes). I tried searching on google, all I could find out is, how to display ePub file and how to customize the look of ePub file. Any suggestion would be great.
Have a look at
Since it's open source, you may be able to tweak it to run on IOS.
Wikipedia's list of ePub editing systems doesn't have an IOS entry yet.