When did they start printing books?

When Aldus Manutius learned how to print fast enough that people could afford his books. Gutenberg was the first to print with movable type, but it took so long to set up a project it was cheaper to copy it by hand with a pen--which is how monasteries supported themselves. Aldus printed little books called Aldine Editions, and sold them for a good price so the common people could have books too.