They both appear to do the same thing, my question has to do with the function and use of each module.
The example site displays one module being used for category/topics and the other for book list.

What becomes blurry to me is the distinction between article, book and blog topics, they are all relatively the same thing. Any advice on the best way to make use of of each in relation to your modules ?

If we use the book module for an article set, do we really need another article section ?