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.
The basics of manufacturing fertiliser. It’s a lot easier to build a civilisation on a full belly.
Also, funny story, I already have a disk like this started.
Ever since covid hit, I’ve been keeping digital copies of several books like the following:
I haven’t gone full “prepper”, but seeing how fast things went sideways at the beginning of covid, it makes me feel a little better to set aside a little bit of hard drive space, just in case.
You can get full offline copies of Wikipedia too, eh? I use Kiwix for most of the stuff on mine.