You can delete address books that you no longer need or require, which is a good habit to get into as it keeps your address book lists free of clutter.
Deleting an address book also clears out the contacts that belonged to it - but it doesn't remove those contacts from the 'All contacts' address book.
Deleting an address book
- Go to Contacts > All contacts.
- Select the check box of the address books you want to delete.
- Select DELETE.
- Select DELETE again to confirm.