The biggest things I fear outside of all of the normal worries is our loss of information And our way to access it. Aka the internet
George, I cannot tell a lie, I am a survivalist and not a prepper. My primary focus is on knowledge. You can download the entire Army military handbooks for free.
The SAS Survival Handbook by John Wiseman and The Survival Medicine Handbook by Joseph Alton/Amy Alton
The above two books are a heck of a good start, and better then the military handbooks IMO. Nevertheless, get the military handbooks too. The SaS survival handbook by John Wiseman also comes in a pocket size edition, literally fits in your pocket, a magnifying glass/ reading glasses for us older guys is a must to read it. I also have the Campers Bible by Bill Riveria, and my old Boy Scouts handbook.
The one book you all should have is the EMT course book, own 2 of them. Medical Pill book, edible plants, etc.
(the below section, not one of the books or manuals did I have to pay for,)
In this digital age, it is easy to download kindle books. I own about a 100 Kindle books: Medicinal plants, 1st Aid, homemade hand sanitizers, Bushcraft, canning & preserving foods, hydroponics, every High School & college course books I ever took( Chemistry, Calculus, Advanced Physics, auto mechanics, Trigonometry, Geometry, to name a few), wilderness survival, cooking books of all ethnic backgrounds( ok i love to cook for me this is a must have necessity), Trapping animals, Plumbing, Electrical household wiring, Construction...
I also downloaded all the Area codes list and Zip codes of USA, USA phonebook on DvDs, Police, Fire, Aircraft Scanner codes, & How to Repair every appliance and electronics that I own (not 1 book but many)
Assuming that won't be accessible, I've been putting together a small library of books similar to what you're looking for. Took a pic today which shows most of them...
You are beginning to grow on me Kauboy, but dear G_d those books are older than I am. Think it is time to get newer editions of the Pill " Drug" books and Symptom books. The Mayo clinic book btw 2 thumbs up for having it mate.
Ok back to you George. The real question is what kind of SHTF occurs. Being a professional wilderness survival writer, I have written several articles on primitive weapons and tools. Honestly if it got that bad, a majority of preppers are gonna be in the crapper ie outhouse. Now if you are referring to the hand tools prior to electricity, well those are quite useful to own. I have used pretty much all of those type of tools in my life, and actually find them kind of nostalgic and fun to use, ( for small jobs).
But to be honest here, having books to build or fix things when one has zero talent in repairing to begin with, is kind of like me saying I bought a book on Music so now I will be able to play Gustav Mahler's symphony #1 perfectly. So point being, the best books to own are ones that would be useful to your skillset. Still get the EMT book, as skilled or not, that could one day save your life, or someone that you care for.