If you care about books, you should know the story of Johannes Gutenberg.
Photo Caption: This Washington Iron Hand Press was manufactured sometime around 1900 and currently sits in the lobby of the Reynolds School of Journalism at the University of Nevada. It is not a Gutenberg press—Gutenberg's press was made from wood—but the design is similar. - Mignon Fogary
Although printing was first invented in China, Johannes Gutenberg invented the European moveable type printing press in Germany sometime between the late 1430s and early 1440s.
He is, of course, the namesake of his most famous book—the Gutenberg Bible, printed in 1452. The Gutenberg Bible, also called the 42-line Bible because each page has 42 lines of text, was one of the first books to be printed in mass production using movable type. Although mass production in this sense still means fewer than 200 identical copies, Gutenberg's printing made the Bible more affordable than the handwritten copies available at the time, which could take more than a year to produce.
The Gutenberg Bible is the most famous book published by Gutenberg, but researchers believe he printed other books earlier, possibly Latin grammar schoolbooks.
Gutenberg's printing process was revolutionary and heralded in the age of printed books and the Renaissance.
His first innovation was a way to efficiently cast individual letters out of metal. When using moveable type, printers have sets of individual metal letters and symbols that they place one at a time to make the template for printing each page. And, of course, everything has to be set in a mirror image of what the final page should look like, so it isn't as straightforward as typing letter-by-letter on a typewriter or computer.
This process of creating books with moveable letters made editing printed books possible in a way that hadn't been possible before. For example, in the earliest printings of the Gutenberg Bible, the first few pages were printed with only 40 lines of type. It was only in the later printings that pages had 42 lines of type. Gutenberg presumably reduced the spacing between lines so he could squeeze in more text and save paper.