Arguably the most important invention in history, the printing press ensured that texts no longer had to be transcribed by hand. This forever removed human error at least in so far as making copies of manuscripts and other documents. Interestingly enough, the first Book ever to be produced off the press was the Latin language Bible.
In its last edition of the 20th Century, Time Magazine considered who was the most important/influential person of the previous millennium. The managing editor of the magazine selected Johannes Gutenberg. He was the clear cut choice. And the reason? He invented the movable type Printing Press in 1445.