Problem adding books.

 
My Bookshelf shows fewer books than total slots, but I cannot add books. What's wrong?
 

Safari subscriptions are based on a total number of slots used, not the total number of books on My Bookshelf. All books in Safari take up 1 slot. You will always be told the slot value of a book before you confirm the addition of a book to My Bookshelf. If you need assistance please contact Customer Service.