The Gothic church building was known as the liber pauporum, the poor people's book, because the walls, windows, and practically any other visible space were adorned with Bible stories and other images that taught important lessons. The illiterate masses, who before Gutenberg could not have bought a book even if they had learned to read, read their church walls to learn the faith. Their windows and other artwork continue to be splendid catalysts for private meditations.
— C. W. McPherson, Keeping Silence