It is often convenient to have a link at the top/bottom of a page that points "Back to" some semantically parent page. This is easily done by using the BackTo template. Use {{BackTo | Parent page title | Optional display text}} to do this. If the optional display text is omitted, the parent page title is automatically used in its lieu.
{{BackTo | Introduction to quantum field theory}} shows up as
Introduction to quantum field theory .
{{BackTo | Introduction to quantum field theory | Back to course main page}} shows up as
Back to course main page .