An essay has been defined in a variety of ways. One definition is a "prose composition with a focused subject of discussion" or a "long, systematic discourse".[2] It is difficult to define the genre into which essays fall. Aldous Huxley, a leading essayist, gives guidance on the subject.[3] He notes that "the essay is a literary device for saying almost everything about almost anything", and adds that "by tradition, almost by definition, the essay is a short piece". Furthermore, Huxley argues that "essays belong to a literary species whose extreme variability can be studied most effectively within a three-poled frame of reference". These three poles (or worlds in which the essay may exist) are: