What are the 4 classifications of the Old Testament?

Most Scholars would agree there are THREE (3) divisions in the Old Testament as follows: Torah (The Law); The Prophets; and The Writings.

This first view is traditionally based on the Hebrew Bible also known as the Tanakh. An alternate view traditionally based on the Orthodox Christian Old Testament divides the books in 4 major categories: Pentateuch (Law); Historical Books; Poetic Books; and Prophets. Basically the Writings division is further separated into history and poetic books.