Before print, every book was copied by hand, letter by letter.

Gutenberg cast letters in metal, set them in lines, printed, then used them again.

The press pressed paper onto the inked letters, one sheet at a time.

Set a page once, then pull copy after copy. Example: 19 units of work, not 180.

Around 1440, Gutenberg invented the movable-type press; by 1455 the first Bibles were finished.

One set of letters, many copies: that is why books became cheaper and spread.