Books specifically for children existed by the 17th century. Before that, books were written mainly for adults – although some later became popular with children. In Europe, Gutenberg’s invention of the printing press around 1440 made possible mass production of books, though the first printed books were quite expensive and remained so for a long time. Gradually, however, improvements in printing technology lowered the costs of publishing and made books more affordable to the working classes, who were also likely to buy smaller and cheaper broadsides, chapbooks, pamphlets, tracts, and early newspapers, all of which were widely available before 1800.