Abstract: A user interface for navigating among screens on a personal computer. The screens, which include layers of a shell user interface and various locations within applications, are presented as pages. In addition, commands and help information of an application are presented as a web of command pages. To this end, a unit of measure, called a “place” is defined. In general, an application is a place, and separate documents within an application may also define a place. Separate command windows and dialog boxes within an application or a document typically do not define a place. Backwards navigation takes the user to the previous place, and forward navigation (if possible) takes the user to the next place. Because the underlying data for a page may change between an initial visit to a page and navigation back to the page, data objects and page code are maintained separately, and are combined only when a request for a page is made.