The museum is one of the oldest printing museums in the world and houses two copies of the famous Gutenberg Bible printed by Johannes Gutenberg, in Mainz, Germany, in the 1450s. Only 21 complete copies have survived. Most were destroyed in World War II. I've also seen the copy located in the New York Public Library which was the first copy to go to the US.
Johannes Gutenberg born in Mainz around 1398, invented mechanical movable type which enabled the distribution of knowledge to the masses. Although different portraits of Johannes exist, none of them are authentic as he died a relatively poor and unknown person on February 3, 1468.