section_path: History/19th century to present
section_name: 19th century to present
paragraph_text: 19th century to present
  
  Steam-powered printing presses became popular in the early 19th century. These machines could print 1,100 sheets per hour, but workers could only set 2,000 letters per hour. Monotype and linotype typesetting machines were introduced in the late 19th century. They could set more than 6,000 letters per hour and an entire line of type at once. There have been numerous improvements in the printing press. In mid-20th century, European book production had risen to over 200,000 titles per year.
  
  During the 20th century, libraries faced an ever-increasing rate of publishing, sometimes called an information explosion. The advent of electronic publishing and the internet means that new information is often published online rather than in printed books, for example through a digital library. " Print on demand " technologies, which make it possible to print as few as one book at a time, have made self-publishing (and vanity publishing) much easier and more affordable, and has allowed publishers to keep low-selling books in print rather than declaring them out of print.