Abstract: A method and apparatus for control of a handheld miniature personal digital assistant, based on a user interface with a menu and thumbwheel. The device consists of a microprocessor, memory, display, thumbwheel, and button. The display presents a sequence of menu items, with one such item designated as tentatively selected by displaying it in reverse video. Rotating the thumbwheel results in moving the designation of an item in the menu, while pressing the button selects an item. The thumbwheel itself can serve as the button if it is pressed rather than rotated. The use of complex menus that display items in two dimensions allows the use of sophisticated applications, including those that require the entry of alphanumeric data, such as a telephone and address directory and datebook. The approach makes such applications feasible in a credit-card-sized package; without the necessity of a keyboard, allowing most of the surface area of the package to be devoted to a display.