The Old Testament is a collection of 39 books. These books cover the time between the creation of the universe and the time before Jesus' birth. The Old Testament is made up of the Pentateuch, the historical section, the poetic section and the prophetic section.
The Pentateuch is the collection of the first five books of the Bible, from Genesis to Deuteronomy. This section covers the time between the creation of the universe and Israel's entrance into the Promised Land. The historical section is made up of 12 books, from Joshua to Esther, that cover Israel's history from its entrance into the Promised Land until the Medo-Persian era. The poetic section is the collection of 5 books, from Job to Song of Solomon. The prophetic section makes up the remaining 17 books of the Old Testament, beginning with Isaiah and ending with Malachi.