Nib asked, and Nib — askNib's tutor — drew the answer live at a whiteboard. This is the spoken transcript; enable JavaScript to watch it drawn.
How did the printing press take over Europe in fifty years? (for a curious adult who has not studied history). Cover, in this order: How were books made before the printing press?; What exactly did Gutenberg invent?; Wasn't printing invented earlier in China and Korea?; Why did printing jump from city to city instead of spreading like a ripple?; Why did books become so much cheaper?; What changed once many people could read the same words? — page 1: Books Before Print
Imagine no printers, no copiers. To get a second copy of a book, someone must sit down and rewrite every single word.
Original book on the left, blank book on the right. The scribe copies line by line, letter by letter, with a quill. No shortcut exists.
The copyists were trained scribes, many of them monks in monasteries, later also workers in city workshops. Neat, steady handwriting took years to learn.
A large book, like a Bible, could take many months of steady work. Decorated letters, painted pictures, and binding added even more hours.
Materials added cost. Many books used parchment, made from treated animal skin, and a big book could need many skins. Still, labor cost most.
So books were priced like treasures, owned mostly by churches, universities, and the rich. And since people copied them, small mistakes crept in with each copy.
Hold onto this: when every book costs months of a person's life, books stay rare, and that is the wall printing was about to break.