Convert IBOOKS to EPUB

Unfortunately, there seems to be no simple way how to convert iBooks file to ePub. If you have access to the .iba source, you can recreate the book and export as ePUB. Alternatively, you can try to achieve ibooks to epub conversion through PDF file, but that means losing some advanced data, such as bookmarks. Should you wish, you can potentially export ibooks to pdf using the Apple software, and then use one of the pdf to epub converters. But as was said, the result will be somewhat poor.