A brief guide by Adafruit on the Apple Newton. It includes info on getting an emulator up and running.
[Some] features of the Newton that were new at the time are common now. Data is stored in databases called soups and programs can access soups from other programs, so the calendar can see contacts in the address book or the notes app can see your calendar appointments. If you’re used to modern iOS or Android that seems like a basic thing, but it was new on the Newton.
The end of the Newton product line coincided with Steve Jobs return to Apple in 1997. Sales had been slow anyway, but Jobs didn’t like the device and famously hated the stylus. He killed it off but held onto the good parts for the iPhone 10 years later.
You can still find plenty of Newtons for sale, the earlier versions are more affordable but the later, more capable ones fetch a few hundred dollars. Luckily there’s an emulator so let’s install that and check it out!