A handheld data processing device having three functional components assembled in a sliding configuration. A processor module is mechanically coupled to two sliding covers. The processor module houses circuits for performing the functions of data processing and may also include a display and input/output functionality. The two sliding covers provide protection for the processor module and may include input/output transducers such as a keypad, speaker or microphone. Embodiments of the handheld data processing device include a handheld computer, wireless telephone and handheld video display. Used as a telephone, the sliders may house a speaker and a microphone.