Many a times when reading a long document it is quite difficult to navigate from one part to another.
However if you have used headings and styles correct you can enable a live table of contents called the Document Map
In Word 2007 On the View tab, in the Show/Hide group, click Document Map.


A new pane will appear on the left hand side with list of all headings and sub headings. Click on any link and you will reach that part of the document.

Isn’t it nice???
You can right click on any heading to choose the correct visible level.
Note: Document Map will not be printed
Click to see detailed video