Copyright gives the creator of an original 'work of literature, science or art' the exclusive right to publish and/or duplicate it. For example, if you have written a book or created a work of art, you will want to prevent others from publishing or duplicating your work without your permission. Copyright is established automatically as soon as a work is created, provided that said work is original.
Ancillary rights protect performances by performing artists, producers of phonograms, first recordings of films and broadcasting organizations. Registering a copyright creates a clearer and, if challenged, more defensible right.