The title is a bit over dramatic but, per the title, if you could contribute with one piece of knowledge to a book that every single individual should learn from in order to kickstart a civilization, what would be yours?
My personal choice would be the process of soap making, from scratch.
There’s also the “How To Make Everything” YouTube channel. I wonder if the guy that runs that has written a book yet? If not, he should.
There’s How to Invent Everything by Ryan North.
IIRC it’s a pretty skinny book, though, so it’s probably light on important details.
Interesting, I will have to check that out.