These free manuals from the military can be a good starting point for your prepper library. They cover plenty of topics but are concise and easy to understand. The manuals are written for everyone- from privates all the way up to generals so they are easy for anyone to follow in stressful situations.
- FM 21-76 Survival Manual – The broad US Army survival manual covers a wide range of survival topics.
- FM 21-76-1 Survival, Evasion, and Recovery – This is shorter, smaller, and more concise than the above manual- meant to be a pocket guide.
- FM 31-70 Basic Cold Weather Manual – Clothing, movement, combat, and survival are all geared for cold weather in this guide.
- FM 3-06 Urban Operations – This manual covers WMDs, asymmetrical threats, and many other urban warfare considerations.
- FM 5-103 Survivability – This field manual is focused on combat survivability and command-level planning to improve it with positioning, camouflage, etc.
- TM 31-210 Improvised Munitions Handbook – A whole handbook on improvised munitions goes into detail about how to make the basics, like black powder.
- ST 31-91B Special Forces Medical Handbook – A 400+ page medical handbook that covers a large range of medical topics.