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.
You don’t need distillation to make beer though, do you?
Nope. Just fermentation.
Sorry that was unclear. I can make beer and I bet I can make liquor too.