Anything that has a basis in fact can be called non-fiction. That means reportage, textbooks, manuals, self-help, memoir, history, guidebooks, and so on, all come under the umbrella of this almost-too-broad term. Its very breadth, however, lends it a richness that has allowed it to dominate a large part of the global book market. In recent years, sales of nonfiction have been outpacing fiction year-on-year.
The word ‘non-fiction’ made its first-ever appearance in the annual trustees’ report of Boston Public Library in 1867, and debuted in the Oxford English Dictionary in 1903. The word ‘fiction’, on the other hand, has a direct root in Latin, came to English via Old French, and has been used to mean imaginative prose since the 1590s.
You can read more about the difference between fiction and non-fiction and their way into the hearts of readers worldwide here.