What is a parable and why do you suppose Steinbeck calls are attention to this in his preface?

A parable is a succinct, didactic story, in prose or verse, that illustrates one or more instructive lessons or principles. It differs from a fable in that fables employ animals, plants, inanimate objects, or forces of nature as characters, while parables feature human characters.

John Steinbeck calls attention to the fact that his novel, "Of Mice and Men," is a parable in his preface because he wants the reader to understand that the story is not just a simple tale of two migrant ranch workers, but that it contains deeper, symbolic meanings and universal truths. The use of the term "parable" suggests that the novel explores broader themes and offers moral or ethical lessons that transcend the specific events and characters in the story. By labeling it as a parable, Steinbeck invites readers to look beyond the surface narrative and contemplate the underlying messages and significance of the events and interactions within the novel.