Mesopotamian scholarship treated the world as legible. The gods were held to write their intentions into things, and trained specialists were employed to read them.
Extispicy, the examination of a sheep's liver and entrails, was the high-status method, with clay models and long compendia used in training. Celestial omens were collected in a vast series covering the moon, sun, planets, weather and earthquakes, and the correspondence of Assyrian court scholars in the seventh century BCE shows kings receiving continual reports and advice. The astronomical records kept for this purpose ran for centuries and were precise enough to be of use to later Greek astronomers, which is a by-product of divination rather than its aim. An unfavourable omen was not a fixed sentence: rituals existed to avert it, including the substitute-king rite, in which another man occupied the throne to absorb a predicted danger.
The narrative literature survives mostly on tablets from scribal libraries, above all the Assyrian royal collection at Nineveh. Enuma Elish relates Marduk's defeat of Tiamat, the making of the world from her body, and the creation of humanity to carry the gods' workload. Atrahasis and the flood episode within the Epic of Gilgamesh describe a deluge sent against a noisy and overpopulated humanity, and a survivor instructed to build a boat. The resemblance to the biblical flood narrative was recognised as soon as the tablets were read in the 1870s and has been argued over ever since.
The underworld in these texts is bleak and universal. It is a house of dust from which there is no return, where the dead are said to eat clay, and it is not divided by merit. What made a difference was not virtue but whether the living kept up the offerings, and therefore whether one had descendants to make them. The unburied and the unremembered were worst off, and were thought capable of troubling the living.