Get a decent (physical) textbook on certain subjects.
EMT training
Survival training
Chemical applications
Electrical applications
Farming/Gardening
They can’t amend your books.
You are 100 per cent correct. And the older the book, the better, unless the technology has changed.
I purchased these books a few years ago, and they are pretty good for a broad spectrum of information. While you can tell they are a bit "hippie" in nature (I did buy them at a Vermont Country Store) but they have good information on how to grow, acquire, store, and cook various foods without a grocery store being available. Otherwise, they seem obviously a bit earthy-crunchy in nature.

This covers everything from "Making Potpurri" to "Buying and Selling a horse"

This covers everything from "Abcesses" to "Yeast Infections". However, this book is focused on herbal and homeopathic types of treatments, and says little about real first aid. I think it has value, because when you have no pharmacy to go to, having alternatives is useful.
For that reason, I am also going to get serious, focused books on medical information and other subjects. And these are not books I could throw in a backpack and run away with, but I am approaching a phase of my life that probably won't be a viable option anyway.
Yay, books! I have gobs of them. As usual, I’m hanging in right there with you.