Ezra - Written traditionally by the priest Ezra himself. (See Ezr 7:11)
Nehemiah - This book itself is named "the words of Nehemiah" (Ne 1:1). However according to Jewish tradition, it believes that the words themselves of the book were placed on paper by Ezra.
Esther - Not accurately known. Could likely have been authored by Ezra, Nehemiah, or Mordecai.
Job - Not accurately known. Though many scholars believe either Moses or Solomon were responsible for its transcription.
Psalms - Written by various authors, however half of the book itself is accredited to King David. Many other names are noted as well which include King Solomon, Moses, Asaph, Ethan, and the sons of Korah. Many psalms themselves do not mention an author.
Proverbs - Chapters one through twenty-nine were authored by King Solomon himself, while chapters thirty and thirty-one were written by Agur and Lemuel.
Ecclesiastes - Not accurately known. But most likely Solomon as the author is described as "the son of David" (Ec 1:1) and "king over Israel in Jerusalem" (Ec 1:12), and says he possessed "more wisdom than all they that have been before me" (Ec 1:16).
Song of Solomon (or Song of Songs) - Traditionally attributed to King Solomon (So 1:1). Yet others question if the song "of Solomon" is like the psalms "of David" - which would mean they're by, for, or about him.
Daniel - Authored likely by Daniel himself, however some scholars question this as chapters seven through twelve are written in first person point of view, "I Daniel" (Da 7:15), however the first six chapters are in the third person point of view, "Then Daniel answered," (Da 2:14).
Hosea - Most likely Prophet Hosea himself, however it is evident that the book itself is written in both the first person and third person viewpoints.
Obadiah - Transcribed by Obadiah (Ob 1:1), or possibly by an individual by said name. Other possibility could be an unknown prophet for whom the title "Obadiah" is given, as the origin of the name itself means "Servant of God."
Jonah - Not accurately known; as the story itself is of Jonah, but it is authored in the third person point of view.
Micah - Prophet Micah either dictated the prophecies he received from God to another who transcribed his words into text or wrote them himself. "The word of the Lord that came to Micah the Morasthite." (See Mic 1:1)