The Book of Job- Antediluvian Literature

Was the Book of Job pre-flood? The ESV translation introduces the book of Job like this: “Considered both a theological and a literary masterpiece, the book of Job is an honest portrayal of God allowing a good man to suffer.” The introduction ends by saying, “The unknown author was probably an Israelite writing sometime between 1500 and 500 B.C.” but is this true? Why do they say that?