Suppose you rented a time machine and it broke down, stranding you in the past, possibly in the distant past. If you’re fortunate enough to find yourself marooned at some point after biologically modern humans first make their appearance (around 200,000 years ago), you may survive. After all, they did, which means there is at least somewhere you can find a suitable climate and things that you can, if hungry enough, safely eat. But since you’re accustomed to conveniences such as palatable food, clothing, and toilet paper, this survival guide ostensibly informs the reader how to build a semblance of modern civilization from the things around them in whatever time period they find themselves in, and hopefully do it much faster than it took originally (which was an embarrassingly long time).
To my mind, that’s the takeaway from this book. We think we’re smart (collectively, at least), and, with no sense of irony, we put the word sapiens in our species name (twice). But when we look back, that assessment seems far from obvious. Sure, our ancestors used cool things like fire and stone tools, even before they were actual humans, but it took people who were biologically indistinguishable from us almost 200,000 years to invent, well, pretty much anything else. For the vast majority of our species’ existence, we didn’t know how to grow food or make cloth or write, let alone know how to effectively treat or prevent illnesses. We’ve only gotten reasonably good at that in the last century or so. If humans are so smart, why didn’t we figure this stuff out earlier?
The book doesn’t really address that question, other than to imply that we may not be quite as smart as we like to imagine. But, with the information it does provide, the stranded time traveler can get civilization up and running in far less time. It would be interesting to run a simulation to see if that might be true. I rather doubt it, and that’s partly because of another important question beyond the scope of this otherwise entertaining and informative book. How would the stranded time traveler avoid being eaten, enslaved, burned at the stake, or otherwise inconvenienced by the first people he or she ran into? Prior to modern civilization, these were common ways of greeting strangers. But, if time travelers did survive, and if they could somehow get people to understand, believe, and follow them (probably in that order), and if they could then avoid the wrath of the chiefs, priests, kings, or emperors whose authority they might be undermining, then maybe they could avoid a few centuries of even millennia of cultural and technological stagnation. Maybe.
Of course, this isn’t really a survival guide, or even a book on how to build a civilization from scratch. It’s an overview of human progress that highlights some of the key ideas, discoveries, and inventions that made modern civilization possible. It does a fine job with that.