Sync iBooks between iPad and iPhone
Mini & MacBook, Mac OS X (10.6.2)
Mini & MacBook, Mac OS X (10.6.2)
If it's not an iBookstore purchase (if it is, and if it's still in the store, you can redownload it via the Purchased tab in the iBooks app on your iPad) you could potentially use iCloud Drive for the app (which wasn't available when this thread was started 7 years ago) : Use iCloud Drive or iBooks to access your PDF files, ePub files, and books - Apple Support
Chris Portman wrote:
I have yet to see any evidence that iBooks is capable of syncing between separate devices (iPhone 4 & iPad)
Tamara wrote:
Actually, bookmarks sync over the air.
Sync iBooks between iPad and iPhone