The Newton platform was a PDA that used a stylus as an input device. It started development by Apple in 1987 was able to convert handwritten text into typed text using handwriting recognition software.
The picture is of a MessagePad 2000, which runs the Newton OS. The first model in the Apple Newton MessagePad line came out in 1993. Over the life of the series, there were many models including the eMate 300, MessagePad, MessagePad 100, MessagePad 110, MessagePad 120, MessagePad 130, and MessagePad 2100.
Using the Newton OS and Stylus, you can take notes using the Notes program, store contact information in Names, schedule appointments in Dates, and use other programs.