In 1968, Alan Kay created the Dynabook, considered to be the first prototype tablet. Never actually manufactured, the prototype used a hardware keyboard (true touch screens were years off) as well as an operating system designed to give children access to digital media. The concept reportedly inspired generations of tablets and laptops.

More than two decades later, the tablet has evolved into what we now call the iPad, the Galaxy Tab, and the Microsoft Surface. It's the latter tablet that the technology industry has focused on of late, with the specs and pricing of the Surface with Windows RT disclosed on Tuesday. A brief hands on with the Surface in June indicated that Microsoft put a lot of thought into it.

That's no coincidence. Dating back to 1991, when Microsoft's Bill Gates began talking about a prototype, tablet computing has evolved as Microsoft has. In its early days, the tablet was merely a tablet interface overlaid onto Windows XP and the other Microsoft operating systems. Over time, the hardware improved, to the point that it enabled new features, including longer battery life and better digitizer input. Interestingly enough, the definitions changed, too: in the past, "convertible" meant a tablet whose keyboard could be folded back over itself, transforming from a traditional notebook into a something akin to a slate or slab.

With the Surface, of course, Microsoft has moved to make the "Metro" tablet UI dominant, subsuming the traditional Windows desktop for those who prefer to work in that environment.

In the following pages, check out a few of the historical precedents to the Surface, including the table formerly known as Surface, now called PixelSense. Bit of a branding issue there, certainly!