the oldest known printed text to have survived to present day is called the Diamond Sutra. it is a buddhist text dated to may of the year 868. it is housed at the british library. anyhow, they have a nice online exhibit dealing with the Diamond Sutra, the history of early printing, and the the silk road. they include many images and it’s all very interesting. but even more interesting is the larger collection of texts which they have digitized. using a shockwave method they call “turning the pages” you can flip through these old texts at your leisure. includes, among other treasures, one of leonardo’s notebooks. very nice.