A treeview control helps users navigate a large site because they can expand and collapse nodes to keep the view manageable. A good example is the Microsoft Developer Network Online Library. You can get a free treeview applet from Microsoft. The applet is bundled with the HTML Help Workshop. You can download the Help Workshop at http://msdn.microsoft.com/library/tools/htmlhelp/wkshp/htmlhelp.EXE. For details on using the control, check this page: http://msdn.microsoft.com/library/officedev/odeopg/deconworkingwithhtmlhelpjavaapplet.htm. For best performance, detect the browser and use the ActiveX version of the treeview control for visitors who use Internet Explorer and Windows.