The Gutenberg Bible
The Gutenberg Bible was the first book ever printed on a press, and to obtain one has become the white whale of book collecting (don't harpoon one though; that is definitely frowned upon). The surviving 48 copies are worth roughly $7 million each, because of their rarity, cultural significance, and gorgeous lettering. They were made in 1455 by Johannes Gutenberg, a German blacksmith who became famous for inventing the first movable-type printing press. Before this enormous revolution, every book had to be hand-copied by scribes, which took forever and led to many inconsistencies from copy to copy. The Gutenberg Bible ushered in a new age of information technology, in which every book was identical, beautifully designed, and swiftly available to a mass audience.