I'm looking for good starting sources about the Sumerians in particular but also Mesopotamia and the Indus River Valley civilizations. I'm a novice historian interested in the origins of human civilization. All help is appreciated
The AskHistorians reading list has an extensive section for books about Mesopotamia and the Sumerians.
For the IVC, I recommend Kenoyer's Ancient Cities of the Indus Valley Civilization, Ancient Indus: Urbanism, Economy, and Society by Rita Wright, and Indus Civilization: a contemporary perspective by Gregory Possehl. The Archaeology of South Asia From the Indus to Asoka, c. 6500 BCE–200 CE is the best and most recent synopsis of the archaeology of India, but it is a pretty dense read.