There are two main characters in the book of Jonah. The first main character is the prophet Jonah (whose name means “dove”) son of Amittai for whom the book is named. He hailed from Gath-hepher which was a city in the territory of Zebulun. From the biblical record one finds that Jonah was a prophet during the reign of Jeroboam II in Israel (2 Kings 14.25). This means he lived during the 8th century B.C. The other main character of the book of Jonah is Yahweh, God of Israel. Only Yahweh and Jonah are named. Everyone else in the narrative is anonymous. This shows that God and Jonah are the main characters of the narrative and everyone else is support.
On the one hand, times in Israel in the early 8th century B.C. were better than they had been. During the reign of Jehoahaz Israel’s national power had been greatly diminished by Syria and their internal affairs were regulated by the king of Syria (2 Kings 13.7). However, a change in the throne led to a resurgence of military power that culminated in Jeroboam II restoring the traditional borders of Israel (2 Kings 14.25). No doubt this served to buoy the nation for a time.
On the other hand, these were perilous times for the nation of Israel. The war machine which was the Assyrian nation was sweeping the Mediterranean world and Israel was in its path. In fact, it was because of the Assyrian campaign under Shalmaneser III in the 9th century B.C. that Israel was able to defeat and capture Damascus. It was only a matter of time before Assyria would come just a bit further south and threaten then conquer the northern tribes.
Into this milieu enters Jonah’s story. Jonah is one of many prophets called to prophesy during the 8th century B.C. He had prophesied that Israel’s border would be restored (2 Kings 14.25). Now he is called by God to go and cry against the capital of the Assyrians, Nineveh, for their wickedness.
The book may have been written by Jonah himself. This would put the writing back into the 8th century B.C. However, there are no parts written in the first person. It is written in the third person. It must be noted, though, that if Jonah did not himself write the book, it is impossible to know for certain who authored it. Internal evidence could put the date later than Jonah; in describing Nineveh in 3.3 the past tense is used (“Nineveh was a great city” [italics mine]). So a date after the fall of Nineveh would place the composition of the book after 612 B.C. The book was received as canon among the twelve Minor Prophets as early as 200 B.C. since Sirach 49.10 mentions “the Twelve Prophets.” Therefore, its composition would have to be sometime before that. These various factors, and several others, are why many scholars place the writing of this book in the exilic or post-exilic years
 The list of contemporary prophets includes Hosea, Amos, and, later in that century, Micah and Isaiah.
 See Billy K. Smith and Franklin S. Page, Amos, Obadiah, Jonah, vol. 19B, The New American Commentary (Nashville: Broadman & Holman Publishers, 1995), 206–209. Smith and Page present the case for the pre-exilic/exilic date. The usage of certain words and phrases and the message of Jonah being a rejection of exclusivism and nationalism are the two main arguments which work in favor of a later pre-exilic or exilic date.