Specifically, the millennia or two before the invention of writing. It must have been an era of considerable political complexity that we know almost nothing about.
Was the Uruk Expansion the world's first empire? -Were there ever quipu-like (non-linguistic but complex and flexible enough for imperial administration) record systems used in the Old World? -What was the world's first state? Was there an Indo-European Genghis Khan? -How much political complexity existed on the steppe? What was Southern China like before Han cultural/demographic expansion?
I don't have any academic work to link to or recommend, but this is an interesting and well-reasoned post on the topic: razib.com/wordpress/?cat=2670
Not related directly to any of the questions in the OP, but most of the new genetic evidence is telling us that "pots, not peoples" was a very misguided idea: population replacement really did happen in this era, and often corresponded with changes in material culture. The Bell Beaker people basically genocided the previous inhabitants of the British Isles (eurogenes.blogspot.com/2017/05/the-bell-beaker-behemoth_10.html). On the other hand, the spread of Bell-Beaker culture to the Iberian peninsula was not accompanied by a major genetic change in the population, though it's possible that a new elite brought it with them.
Jaxson Flores
>On the other hand, the spread of Bell-Beaker culture to the Iberian peninsula was not accompanied by a major genetic change in the population
Same in Sardinia
I wonder why the British natives were so easily killed
John Phillips
bell beaker culture started in portugal
Jace Williams
>Sardinians Forgot to talk about EEF/First Farmers in the OP. They were the OG colonizers--not just the Mediterranean littoral, but most of Western Europe as well. Some things that were once controversial about them are now clear: 1. It was a true demic expansion, not just the diffusion of the idea of farming. 2. They didn't speak indo-european.
But we still know very little about them given that a huge chunk of the ancestry of modern Europeans derives from this group. Anyone have more?