In the book the Hobbit I believe the character gollum was manly in the book fore the ring. In the book he only showed up when the ring wase shown. This shows that he was probably used to introduce the ring in the book. This is a reason that most likely put him in the book. One way is in the holl book he wasn't brought in till the moment the ring wase brought into the book. In the book when Bilbo found the ring wase when gollum wase shown in the book. This shows that hise main purpose in the book wase to introduce the ring. This is why I thank that gollum wasn't important character in the book. Second he did have some rolls that hade some meaning. Like in the book he told us what the ring did it gave us an insight of wate Bilbo could do. This