For many Christians, the Old Testament is a "book sealed with seven seals." This is due to the great historical distance and the fact that during an extended period of time became the Old Testament background in the ecclesial conscience average, somewhat displaced by the New Testament. The continuity of both Testaments justify Christian theology devoted to the study of the Old Testament. Without the Old Testament, New is absolutely unintelligible. This Introduction to the Old Testament structure responds to a "historical" and aims to contribute to an exploration based on solid knowledge of the writings of ancient Israel and early Judaism.