The very first book that Gutenberg
/Johann Gutenberg printed
was an edition
of the bible
now known as the Gutenberg bible
. It is very famous
in much the same way as the Penny Black
is very famous for being the first postage stamp
. It was the first and thus a model
that came later.
The Gutenberg bible is not extraordinarily rare, it is, however, useful as a popular tool for promoting libraries and archives due to its fame. It was typeset in such a way that it could illuminated by hand. The intellectual content of the Gutenberg bible approaches zero cost, since books with equivalent content/identical content are now mass produced by many commercial and religious printers.