The Merck Manual (2011)

Before AI, we had the Merck Manual, compendium of all things Medical and Pharmaceutical Related

A very ancient symbol going back into distant antiquity

I would recommend that as with the Holy Bible, you have a hardcopy of this one in addition to digital.

This has been regarded as must-acquire by survivalists going all the way back to Kurt Saxon in the 1970’s who put it in his top ten list of books all preppers should own.