Tablet PCs are actually an old concept. In the late 90s a few manufacturers tried making them for the mass market, but the market simply wasn’t ready for them. Apple got the ball rolling again in 2010, releasing the original iPad. They made even greater waves in 2011 with the iPad 2. They’ve since released another iPad, and retain dominance over the tablet PC market. Android has checked in with a number of competitors, and will continue to play catch-up with the iPad.