The big picture
Historical article · Originally published February 23, 2003; technical details may be outdated.
The Code Explorer
The CodeSMART Code Explorer is a navigational and management tool that integrates features from both the standard Solution Explorer and the standard Class View. For a solution and its projects, it displays a single hierarchical list with all the contained items, from files and folders down to functions and variables. 
[via CodeSmart.NET Screenshots page]
again, coolness.