'Long ago there were civilisations so far in advance of us that we cannot begin to imagine what they were.'
'How do we know?'
'About five thousand years ago there was a terrible storm in a desert that everyone thought had always been a desert, just piles of sand, and the storm shifted the sand and exposed a city. It was very big. It had been made to keep chronicles - records - books.' ...
.... 'Some wrote it all down but others were trained to remember. And that is where all our knowledge comes from - those old libraries. But it was just as well the Memories were trained, because when the books were exposed to air they crumbled into dust and soon there weren't many left.'