Drifting off topic somewhat, but I would say most relevant at the moment in terms of survival is how to survive the winter without recourse to the local foodbank and if the electricity is cut off. It is too real a scenario for many at the moment.
I am busy pickling some of the surplus from my allotment, it's a lost art I reckon, it is very hard to find pickling vinegar in quantities like you used to.
Fortunately that is where the local Indian supermarkets come in, not everyone has abandoned the old frugal ways.