Johannes Gutenberg used movable type for the first time in 1451. Prior to his invention, monks and copyists copied books by hand. Therefore, books were rare and expensive. He cast his type from sand molds and adapted woodcut presses to hold his type. Gutenberg is most remembered for his 42-line Bibles, called such because each page was 42 lines long. About 40 such Bibles remain and are extremely valuable. Children could learn more at: Gutenberg.