A novel is an invented story presented in book form. Writers of novels are often referred to as novelists.
The novel is often defined as being a fiction in prose of a certain length, typically more than 50 000 words, with characters, incidents and perhaps a plot. This admits of counterexamples: many novels, among them Ulysses by James Joyce and Moby-Dick by Herman Melville, contain passages written in drama or verse form. Historical (non-fictional) novels, such as I, Claudius by Robert Graves are a well-established subclass of novels. Some, perhaps Rainer Maria Rilke's Notebooks of Malte Laurids Brigge, contain little or nothing in the way of a plot.
Novels are a relatively recent genre, first flourishing widely in the early 18th century in Europe. Miguel Cervantes is credited with writing the first Western novel, Don Quixote, the first part of which was published in 1605. But the Chinese Romance of the Three Kingdoms predates this by centuries and is easily a novel by modern standards. The Tale of Genji, by Murasaki Shikibu (a Japanese noblewoman), was written even earlier, in the early 11th century, and is often considered to be the world's first novel. Still, many Greek and Latin narratives may also fit that description, including The Golden Ass by Apuleius, a 2nd century Latin author from North Africa. In it we find the characteristics that even today make up a novel. The first English language novelist was Daniel Defoe who wrote Robinson Crusoe in 1719.
Prior to the rise of the novel very little work written in prose was taken seriously as artistic literature. People used prose for science, law, history, and philosophy, but the general attitude was that work written without poetry could hardly count as aesthetically interesting on its own. The early novel was meant to reach a large public and at the beginning it was considered as a lower form of literature - neither true nor beautiful. The novel is thus historically linked with realism in style and content, but this can no longer be considered generally true. The discovery of the wealth of aesthetic value that inheres in prose not constrained by poetic structures can be considered a major development in world literature.
What sets the novel apart from a short story is that it is longer, more complex, and deals with more than one issue in the lives of its characters. What sets it apart from a play is that it is not confined by the restrictions of the stage, human actors and the audience. What sets it apart from poetry is that it is written in prose form.
See: literature, the short story, theater, poetry, novellaThe novel and other literary genres