What was very scarce during the middle ages

The Middle Ages, or what many preferred to call as the Dark Ages, was on of the times that the history of human beings took another turn. In this age, what was very scarce during that time were books. It was referred as the Dark Ages to being with because literary and cultural output were all very limited to the point that the general public aren't that well informed about the anything. This was indeed a dark age since there were many problems that arouse together with the scarcity of literary and cultural outputs. When Renaissance came, which meant enlightenment, the course of history once again took a turn towards the advancement of human race.