Broad book categories are adult fiction, non-fiction, and children. Popular non-fiction includes cookbooks, diet, self-help, and how-to books. One popular children's title was the McGuffey's Readers.
Many books are printed in hardcover first and paperback later. Paperbacks are cheaper, and are more portable due to their smaller size. 70,000 books are published each year.
Communication theorists consider book readers to be "opinion makers."
US citizens read fewer books per person than any other English-speaking country.