TOC Book Item without an associated page

I may well be missing the point here - no change there, then! - but how (in RH7) do I get a sub-section, a book within a book, into the left navigation but not have a link with its name in the breadcrumbs appear in the main content pages? Or can I not do that? It just seems a bit lame to have it there since I've not associated a page to the book and don't want to.