I've been doing many posts on rules building lately, but that can get rather dry especially from the spectator's point of view. So let's go back to world building.
Please excuse the glut of resources from these gamer-centric supplements. I got an unbeatable deal on a whole bundle of them and they are all such casual reads that I can usually start and finish one within a single evening.
Farm, Forge, and Steal: A Nuts and Bolts Guide to Civilisations by Phillip McGregor attempts to "define the limits (“rules”, if you will) that define premodern societies and civilisations ... the constraints under which they operate, knowingly or unknowingly. This will allow GMs to design believable campaigns that are no less fun, “cool”, or different for being realistic."
The title immediately reminds me of Jared Diamond's Guns, Germs, and Steel: The Fates of Human Societies. Not surprisingly, Diamond's work appears in McGregor's annotated bibliography while Guns, Germs, and Steel sits on my bookshelf waiting in line to be read.
Regardless, McGreggor does a good job of breaking down civilization (I will revert to the American spelling, damn Aussies) into a number of discrete points as evidenced by their overall level of technology. His take home lessons are conveniently highlighted in little "so what" call outs that present brief rules for a believable civilization.
The author starts off relatively simple by stating that civilizations establish themselves in areas rich with wild food and develop first semi-permanent then permanent settlements, leading to agriculture and animal husbandry. I like the emphasis on putting the establishment of permanent settlements and agriculture in their proper order despite what common knowledge might dictate.
McGreggor then moves forward with the emphatic statement that "population dense agriculture
trump[s] population diffuse nomadism (hunter-gatherer/herding). Always." I will come back to this point in a follow up post as it gives me an interesting idea for some game lore. Either way, from here, he moves forward through time.
McGreggor does a good job layering advances in technology together with growing civilizations. He earns points with me especially in pointing out the complicated dependencies of technology and how certain inventions require previous steps in civilization maturity and not just from a technical sense.
For example, the primary source of power for pre industrial society would be burning wood and charcoal. This was an especially convenient power source since the fuel was ubiquitous in Europe's vast forests and could be harvested with muscle power. However, these fuels also had a significant drawback, people had to choose between food and fuel, or between farms and forests. Throw in the slow but inevitable decline of Europe's forests and the need for an alternative fuel supply blossoms.
The answer eventually came in the form of coal, but mining in this era was very limited. Mines could only be dug so far below the water table before muscle-powered pumps could no longer keep the mine dry. So one of the first applications of steam engines was to create more powerful pumps in order to mine the fuel for those pumps and the rest of the emerging industries. This concentration of energy and power provides the catalyst for condensing industry from cottages to factories, and now you are off to the races (or Industrial Revolution).
Ultimately, the author succeeds in helping to set the foundation for how civilizations operate and his material is readily accessible. McGreggor lays out some of the fundamental stepping stones of societies as they develop towards modernity as well as creating the logical framework for why certain technologies were or were not created at a particular point in history. He provides good scaffolding for the critical evaluation of the campaign world/society that you are crafting.