9REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Ancient History: 4500 BC to 500 AD discusses Mesopotamian civilization, Egyptian civilization, Hebrew civilization, Greek civilization, Alexander and the Hellenistic Age, the Roman Republic and the Roman Empire, and Christianity in the ancient world.