Why did kramer call the devlopment of writing sumer's most significant contribution to civilization?

Kramer regarded the development of writing as Sumer's most significant contribution to civilization because it facilitated the recording and transmission of knowledge, laws, and cultural practices, which were essential for the administration and organization of complex societies. Writing enabled the preservation of historical records, literature, and religious texts, fostering continuity and cultural identity. It also allowed for more sophisticated communication and record-keeping, essential for trade and governance, ultimately laying the foundation for future civilizations.