The limitations of palmtop computers are their display size and pointing mechanisms. This makes it difficult to use them for direct manipulation of very large objects, such as World Wide Web (WWW) pages, newspapers, maps, and documents that require a large display. This paper describes a new palmtop computer with a built-in mouse on the underside of the computer. When a user moves the computer on a table, the display scrolls as if the user is moving a window frame over a large document. Experiments using a prototype have shown that locating targets outside of the display is as easy as targets within the display.