Literary fiction is a term used to describe fiction that explores any facet of the human condition, and may involve social commentary. It is often regarded as having more artistic merit than genre fiction, especially the most commercially-oriented types, but this has been contested in recent years, with the serious study of genre fiction within universities. Prior to the 19th century, poetry was commonly understood to be something set in metrical lines; accordingly, in 1658 a definition of poetry is "any kind of subject consisting of Rhythm or Verses". Although there are many historical prototypes, so-called "novels before the novel". The novella exists between the novel and short story; the publisher Melville House classifies it as "too short to be a novel, too long to be a short story". A dilemma in defining the "short story" as a literary form is how to do it, and whether one should. It has been tried a number of times in the past, however without much success; the quest continues.