You can open and export digital ebooks in Apple iBooks file format (.ibooks) to PDF document format using the export function in iBooks Author on macOS / OS X. You may however lose some functionality of ibooks format.
Books created with iBooks Author can only be viewed on an iPad (iOS) or Mac computer. You can export your book to pdf format from this app. That can be viewed on any platform, but various features will be lost.
Updated: February 20, 2017