Book manufacturing in the modern world

The methods used for the printing and binding of books continued fundamentally unchanged from the 15th century into the early years of the 20th century. While there was of course more mechanization, Gutenberg would have had no difficulty in understanding what was going on if he had visited a book printer in 1900.
Gutenberg’s “invention” was the use of movable metal types, assembled into words, lines, and pages and then printed by letterpress. In letterpress printing ink is spread onto the tops of raised metal type, and is transferred onto a sheet of paper which is pressed against the type. Sheet-fed letterpress printing is still available but tends to be used for collector’s books and is now more of an art form than a commercial technique Today, the majority of books are printed by offset lithography in which an image of the material to be printed is photographically or digitally transferred to a flexible metal plate where it is developed to exploit the antipathy between grease (the ink) and water.
When the plate is mounted on the press, water is spread over it. The developed areas of the plate repel water thus allowing the ink to adhere to only those parts of the plate which are to print. The ink is then offset onto a rubbery blanket (to avoid all that water soaking the paper) and then finally to the paper