Young adult fiction or young adult literature (YA) is fiction published for readers in their youth. The age range for young adult fiction is subjective. Some sources claim it ranges from ages 12–18, while authors and readers of "young teen novels" often define it as written for those aged 15 to the early 20s. The terms young adult novel, juvenile novel, teenage fiction, young adult book, etc., refer to the works in this category.
The subject matter and story lines of young adult literature are typically consistent with the age and experience of the main character, but this literature spans the spectrum of fiction genres. Stories that focus on the specific challenges of youth are sometimes referred to as problem novels or coming-of-age novels. According to 2013 statistics by the speculative fiction publisher Tor Books, women outnumbered men by 68% to 32% among submissions of this type of fiction to publishers, a gender distribution converse to that observed in adult science fiction and most fantasy fiction.
The history of young adult literature is tied to the history of how childhood and young adulthood has been perceived. The 1920s "was the first time when it became clear that the young were a separate generation", yet many novels within the young category had been published long before. One early writer to recognize young adults as a distinct group was Sarah Trimmer, who, in 1802, described "young adulthood" as lasting from ages 14 to 21. In her children's literature periodical, The Guardian of Education, Trimmer introduced the terms "Books for Children" (for those under fourteen) and "Books for Young Persons" (for those between fourteen and twenty-one), establishing terms of reference for young adult literature that still remains in use. Nineteenth century literature presents several early works, that appealed to young readers, though not necessarily written for them, including The Swiss Family Robinson (1812), Walter Scott's Waverley (1814), Charles Dickens' Oliver Twist (1838), Alexandre Dumas' The Count of Monte Cristo (1844), Tom Brown's Schooldays (1857), Dickens' Great Expectations (1860), Alice in Wonderland (1865), Mark Twain's The Adventures of Tom Sawyer (1876), and Adventures of Huckleberry Finn (1884), Robert Louis Stevenson's Kidnapped (1886), Rudyard Kipling's The Jungle Book (1894), and Moonfleet (1898) by J. Meade Falkner.