Address books are defined for a profile, not account. You can, of course, create a work address book and a personal address book. When you add a contact from a message by clicking the star, you can specify which address book it's added to (by clicking the star again). Separate address books can be useful in some filters. The address autocomplete function for new messages can be defined so that, e.g., only the work address book is scanned when sending from the work account. It depends on why you want separate address books.