Agreed So, in the new terms, my point is that a top smartphone-like device, being the quintessence and the culmination of technological advancements of our civilization over the millennia passed, filled with the knowledgeably preselected and carefully digitized wisdom of the entire humankind is a significant asset to leverage in any scale disaster from a pico- to giga- level...

By the way, In my digital survival books collection I have a dozen or two of the best schoolbooks of the 20th century (algebra, geometry, chemistry, botany, biology, physics, and so on), in Russian though, as I'm not aware of any good English schoolbooks so far. I also have the famous Russian highest-mathematics pocket thesaurus digitizing project in the work (also using my phone and the great documents scanner app CamScanner for that).