You get to choose whether to show just the highest-level headings, or lower-level headings as well. That is, it shows all the headings in your document. What it shows you, however, can be very useful. It just sits there on the left of your screen. Strictly speaking, it doesn't do anything. You'll see the Document Map on the left of your Word screen. (We lost the old keyboard shortcut in Word 2007, but it was reinstated for Word 2010!!) The first is the Document Map (if you hover over it, the button says 'Browse the headings in your document'). Below the search box, there are three un-named pale buttons.
In Word 2007 and earlier versions: View > Document Map.Figure 1: The three parts to the Navigation Pane in Word 2010
