PADD is the name for eBook Readers given in StarTrek.
Personal Access Display Device (PADD), a hand-held computer interface, used as early as the 22nd century and well into the 24th century. It provided a remote access to the main on-board computer with wireless capability. It could be used to read eBooks but also had a touch screen interface and could be used to provide input the ships computer. The closest device in the present day would be the Home E-Reader which is still in the prototype phase. However, the latest Web Tablets could lead the way to such a device.