Who wrote the Book of Job in the Bible?

It is entirely unknown who wrote the Book of Job. Some scholars suggest that it is in fact the oldest book in Old Testament (and thus in the Bible itself). It is probably based on a poem Ludlul bel nemeqi from Akkadia about 1000 years earlier.

A:

R. N. Whybray (The World of Ancient Israel: Sociological, Anthropological and Political Perspectives, The social world of the wisdom writers) says that there is uncertainty about even the nationality of the author of the Book of Job, as well as about the date it was written. A date in the Persian period (fifth or fourth century BCE) is at present the most favoured one, chiefly because of the speculative nature of the book's theology, especially compared with the older parts of the Book of Proverbs, and the acquaintance of the author with other Old Testament writings such as Isaiah 40-55 and the presence of the Satan as a member of God's heavenly court.

The author had a wide knowledge of the literary world of the ancient Near East outside Palestine. This fact, together with the unexplained peculiarities of the language of the poetical part of the book, has led some scholars to suppose that the author was either a Jew living outside Palestine, or even a non-Jew. However, it is not possible to identify the actual author.