In 1498, for instance, 18,000 letters of indulgence were printed at Barcelona.
The market for books was still small, but literacy had spread beyond the clergy and had reached the emerging middle classes.
It has been at the heart of the expanding intellectual movement of the past 500 years.
Although printing was thought of at first merely as a means of avoiding copying errors, its possibilities for mass-producing written matter soon became evident.
Freedom of the press was pursued and attacked for the next three centuries; but by the end of the 18th century a large measure of freedom had been won in western Europe and North America, and a wide range of printed matter was in circulation.