Recently I copied a few PDFs into iBooks from Windows via Dropbox, and then deleted the files on Dropbox. Little did I know that the files on Dropbox were my only Windows copies (I thought drag-and-drop on Windows to Dropbox would copy the files, not move them). So now I need to get those files from iBooks back to Windows. How do I do it? Dropbox has no option for this that I can find.

Connect your iPad to your computer which should automatically open up itunes, let it sync your iPad and then there should be a drop down menu in the top left hand corner click it and select books. This should bring up all your books/pdfs that are in your iBooks, find the one you want, right click and press copy. Paste wherever you want, hopefully it works!