moshe rabbeinu - If Moses wrote the Book of Job, was he Job's contemporary and writing history or is the Book an inspirational work of fiction?

The Talmud at Bava Basra 14b-15b teaches that Moses wrote the Book of Job before the Exodus. If so, was he a contemporary and a witness to Job's suffering, was he describing a historical figure he didn't know, or was it simply an inspirational fable?

Answer

There are many different opinions regarding when Iyov existed, if at all. Many are mentioned in the Talmud you cited in your question.

The Talmud (Sotah 11A) says that Iyov was one of Pharaoh's advisers along with Yisro and Bilaam. See the details translated here. They advised Pharaoh at the beginning of the Israelite's slavery.

The Talmud (Sotah 35A) brings an opinion that Iyov died shortly before the spied entered the land, a little more than a year after the Jews left Egypt.

The Talmud (Babba Batra 15A) (translation here) says that Moshe told the spies to see if Iyov was in the land.

The Talmud there also brings an opinion that 'The span of Job's life was from the time that Israel entered Egypt till they left it.'

According to Iyov 42:16, Iyov lived 140 years after his suffering. Since Moshe was only 80 at the time of the Exodus, he would not have seen Iyov's suffering.