This subtemplate of {{BOOKPAGENAME}} handles cases where an in-book-style page name has been derived from the name of an associated non-book page.

The in-book-style name is expected as parameter pagename.

This template reparses the derived pagename, however it was derived before calling here, dispatching further deduction to either {{BOOKPAGENAME/inbook}}, {{BOOKPAGENAME/shelf}}, or {{BOOKPAGENAME/department}}. At this writing, the two non-book namespaces that invoke this are template space, where the derivation is trivial, and category space, where derivation is nontrivial and handled by {{BOOKPAGENAME/category}}.