Sumerian-Akkadian mythology reaches back to the earliest lists of gods in the third millennium bce and preoccupied the Mesopotamian intellectuals for more than 2000 years. This overview describes four major moments in the earlier phases of that history, each putting in place a different type of cosmic building block: ontologies, infrastructures, genealogies, and interfaces. These four phases stretch from the first mythological narratives in the mid-third millennium down to the late second and first millennium bce, when Mesopotamian materials are reconfigured and adapted for cuneiform scribal traditions in northern Mesopotamia, Syria and the Levant. Rather than limiting ourselves to late, somewhat heterodox recompilations such as the Enuma Elish or the Baal Epic, this contribution argues that the most important and long-lived features of the mythological tradition in Mesopotamia came into existence between 2500 and 1500bce.Like the poetry of a particular language or the usual turns of phrase in a family, the mythology embedded in a particular culture or civilization provides decisive clues to the central concerns of that society. These clues are indirect hints at most, constrained by the need to transmit specific textual materials (mythologems, proverbs, or narratives), while at the same time producing the local pragmatic effects that they are thought to achieve. Surprisingly, then, mythological materials are also usually quite susceptible to translation, giving the unknowing reader the impression that things were not so very different four thousand years ago in ancient Iraq. If we adopt a definition of myth that limits our quarry to “stories about deities that describe how the basic structures of reality came into existence,” excluding thereby .