Frank,
Short answer: both. The element is primarily a container of meta information about the element that contains it. But what is copyright, isbn, etc? You could argue that it's just meta information for the element (as the Docbook guide does, since it notes that the element is "is confined to meta-information"), but it's also user visible. Remember also that the processing expectations for info read:
Suppressed. Many of the elements in this wrapper may be used in presentation, but they are not generally printed as part of the formatting of the wrapper. The wrapper merely serves to identify where they occur.
So putting it in the elements allow a book publisher to harvest the meta-information for their XML database, while putting it in the body of the document lets you format it properly for print, Web etc.
Now, I notice you're working with a fiction book. You may be better off with the DocBook Publishers schema, rather than the original Docbook. Publisher was designed by the OASIS DocBook Sub Committee for Publishers which was chartered to develop and maintain official variants of DocBook in support of the publishing industry. The DocBook Publishers Schema is based on DocBook 5.0, and delivered in the normative RelaxNG Schema format.
It's a lot easier to work with in that it removes a lot of the technical and software engineering elements from Docbook. It also adds a few elements for poetry, drama and speeches. If you use the Dublin Core metadata, it also adds them as elements for use in blocks.
See: http://docs.oasis-open.org/docbook/specs/publishers-1.0-spec.html
The repository is here: http://docbook.svn.sourceforge.net/viewvc/docbook/trunk/docbook/relaxng/publishers/
I've been developing a schema using Publisher as a base for a particular type of non-fiction book.