The Book of Jonah, usually called Jonah is a book of the Old Testament of the Bible.The book is primarily concerned with the prophet Jonah (Prophet), whom the book is named for. In specific the book gives an account of Jonah's refusal of God's command for Jonah to travel to the the capital of Assyria, Nineveh and prophesy it's destruction to the people. The most notable event of the book is the swallowing and expelling of Jonah by a Great Fish.
The Book of Jonah does not specify any author. The authorship of the book by Jonah in third person is a possibility, as there is no evidence presented in the book or the rest of the Bible against it. There is possibility that another author could have written the book. In that case the author would have had to refer to recordings of Jonah's conversations mentioned in the book, as well as a copy of Jonah's prayer to God.
The Book of Jonah is primarily a historical account. The book records many direct conversations and quotations from the people involved in the conversations. The book also documents one short prophecy concerning Nineveh's destruction and records a royal decree from the King of Nineveh.
There being only four chapters in the book, the entire second chapter (except for a single sentence that mentioned Jonah being expelled from the Great Fish) being a record of Jonah's prayer to God. This effectively makes one fourth of the book poetry. The prayer is very poetic, and stylistic of many of the Psalms, as Psalms was the basis for the nation of Israel's Yahwists in their prayers.