Q: Can't remove a book from iBooks

You are referring to the iBooks app on your iOS device, correct? When you open the Library and see the Books on the shelf, are you indicating that you cannot tap on the "Select" button in the top right-hand corner? Once you do that, you can then tap on the book you want to delete, and a red Delete option will show in the upper left-hand corner next to Move.

Cheers,

GB

dude, same problem here... did you find a solution?

If you do not want to see iCloud books, click on the "All Books" option in the middle of the library screen, then at the bottom of the dropdown, turn on "Hide iCloud Books".

Cheers,

GB

Best bet is to access your account from a computer, not a tablet or phone, and hide the purchase like you would a movie or a song.  Unfortunately, this only works some of the time.  I have one book that stays in my library regardless of what I do, but for most books this seems to work.

Hide and unhide purchases in iTunes or iBooks on your Mac or PC - Apple Support