The History of the Tablet Computer - it goes back further than you think!
While some may argue that tablet computers have been around as early as those introduced in the early 2000's, or even with Apple's own Newton (1987-1998), the idea of a tablet style computer actually goes all the way back to the 1800's. The first patent for an electronic tablet used for handwriting was granted in 1888, though it was an article written by Alan Kay in the early 1970's that best conceptualized what a tablet computer was to become.
The DynaBook - conceptualised by Alan Kay in the late 1960s and early 1970s in his article "A Personal Computer for Children of All Ages"
The DynaBook was to be a tablet-style computer aimed at learning and gathering information. Kay envisioned that DynaBooks could connect wirelessly to centralised information storages, and could "abstract" information from those storages. It was about the size of a notepad, with a hardware keyboard at the bottom, and a screen at the top (using "liquid crystal", a brand-new technology back then). It could also play audio files, record voice memos, and much, much more.
So far, it sounds like a tablet, but you are all wondering where the stylus comes in. Apart from printing the word "stylus" in one the illustrations, there's no further mention of it in the article. In fact Kay takes it all a few steps further: he basically describes a multitouch display. In 1972. That's almost 40 years ago.