Going into detail is the goal in this essay about their importance in what they invented how they are intertwined: specifically farming, irrigation, numeral system (to keep track of crops/harvesting), and sailboats used for trade and commerce and how these things impacted the world.

Here is the book summary the essay should come from, see Chapter 3: https://www.worldsupporter.org/nl/chapter/40055-summary-human-web-birds-eye-view-world-history(there isn’t a lot of details about the Sumerians in this book, but, the ancient Sumerians, the “black-headed ones,” lived in the southern part of what is now Iraq. The heartland of Sumer lay between the Euphrates and Tigris rivers, in what the Greeks later called Mesopotamia.) Going into detail is the goal in this essay about their importance in what they invented how they are intertwined: specifically farming, irrigation, numeral system (to keep track of crops/harvesting), and sailboats used for trade and commerce and how these things impacted the world.