Apple DRM and Adobe DRM are different.
I don't think there is any way of transferring ibooks to read on ADE or on the large number of eReaders that can read Adobe DRM,
short of DRM stripping them.
There may be other apps that can read Apple DRM books in other environments such as PC or Android; but I am not aware of them.
Possibly ADE is able to open the iBook enough to read unencrypted metadata, and thus can show the book in the library.
It fails to decrypt the content, and rather than giving a good error message just displays what it can ... nothing.
from http://en.wikipedia.org/wiki/Digital_rights_management (of course, wikipedia is not always right and may be out of date, but ...)
There are four main ebook DRM schemes in common use today, one each from Amazon, Adobe, Apple, and the Marlin Trust Management Organization (MTMO).
- Amazon's DRM ...
- Adobe's Adept DRM is applied to ePubs and PDFs, and can be read by several third-party ebook readers, as well as Adobe Digital Editions software. Barnes & Noble uses a DRM technology provided by Adobe, and is applied to ePubs and the older Palm format ebooks.
- Apple's Fairplay DRM is applied to ePubs, and can currently only be read by Apple's iBooks app on iOS devices.
- The Marlin DRM ...
You can read any ePub or .acsm book you download from iBooks in an e-reader (I have a Kobo Touch). Once you've signed into iBooks and downloaded the book you want, just drag and drop its title/cover page icon - from the iBooks application - to your desktop. Then, open your ADE application, click on "File" then "Add to Library" Find it in the drop-box (under desktop), and click "add". Make sure your e-reader is connected to your computer. You should see it under "devices" on the left hand side. Click on "All Items" under the heading "Bookshelves", then click and drag the ebook you just downloaded into your e-reader found under "devices." Voila! eject your e-reader from the computer. Your e-reader will have it for you to read.