It was revolutionary of course, but when I came face-to-face with a 1450s Gutenberg bible, with its twin black columns of dense Latin text, I realised that there was another story to tell: the story of humble paper. Paper is nothing special, except that it is far cheaper than animal-skin parchment. It's so cheap that we now use it to wipe our backsides. The cell phone is one, the computer is another.