Nonzero: The Logic of Human Destiny by Robert Wright

There is no consensus on how or why agriculture started. It was a good idea for several reasons and was therefore inevitable as nature’s abundance was bound to run out. It may have started when people started tending wild crops. By weeding and replanting the best plants they were on their way. This would have formed a system of “scattered” gardens that they could turn to as needed. In essence, they were an “insurance” plan for the hunter-gatherer. Gardens even attracted food animals as they do today.
Those with access to more food had higher status and more wives and children. More food caused population growth and when it came to ancient wars, there was nothing more effective than raw manpower. Domesticated plants and animals spread faster east to west due to similar climates. This gave Eurasia a big advantage over Africa and the Americas.

After agriculture first spreads across a region, chiefdoms soon follow. Population density will also do the trick. Chiefs dupe the public into following them and religion is often part of the duping. In short, chiefs are parasites. Their power is finite. Neglecting the public welfare can diminish his own as can losing a war. There are limits to how much greed a chief can get away with. With its increase in population density, farming caused the first revolution in information technology.
The concept of the meme is introduced as “the basic unit of cultural information,” analogous to the gene. Unlike genes, memes can be introduced purposefully rather than randomly. Thus cultures can evolve faster than populations driven by genes.

Like agriculture, writing evolved multiple times. It was first created to keep track of commodities used for early trade. The use of writing for legal codes, religion, and politics followed. Written numerals preceded written words. Couriers or runners were used to move written information within and between states. As complexity evolved from chiefdoms to states, writing evolved at the same time.

When you look at places like the Middle East, China, and the Americas, you see the steady evolution from villages, to chiefdoms, to towns, to city-states, to multi-city states, to empires. That is ancient history in a nutshell. Here Robert provides summaries of the civilizations that developed in the three areas just mentioned. They have their quirks, but the basics are the same.
The civilizations in the Americas lacked draft animals. The Incas did have the Lama, but the Aztecs had the wheel, which for them was essentially a toy. The phonetic alphabet was an advantage for the Middle East. Big ideas in math and science were independently discovered in multiple cultures. Disruptions in trade (non-zero-sum threats) resulted in the growth of governments that gave us roads and laws.

The 410 A.D. sack of Rome by barbarian tribes stands out in history. We should think of the barbarian tribes as mobile chiefdoms rather than uncivilized groups. Sometimes cultures become ossified and need to be rebooted by an invasion. Invaders don’t ditch cultural advance so much as they appropriate them. Think of the culture as “under new management.” Rome was built on slavery, which leads to lower efficiency. Slavery is bad social engineering. So were Rome’s glaring deficits of exploration, authoritarianism, and corrupt self-aggrandizement.