This subtemplate of {{BookCat}} handles the actual categorization of the page, using data provided by the parent template.

Parameters namespace, pagename, and fullpagename are expected.

This template is only a dispatcher, sending talk pages {{BookCat/talk}}, categories (and project pages) to {{BookCat/category}}, subject pages to {{BookCat/subject}}, templates to {{BookCat/template}}, userspace pages to {{BookCat/user}}, mainspace pages with prefix Department: or Shelf: to {{BookCat/department}} or {{BookCat/shelf}} respectively, and anything else to {{BookCat/default}}.