Howdy. I can think of a few.
For general survival ...
Life After Doomsday, by Bruce Clayton. Its focus on nuclear survival, but it does cover "worst case" scenario and long term survival.
It's a Disaster!, by Bill and Janet Liebsch. This book covers all the major types of disasters.
The Guide to Self-Sufficiency, by John Seymour. This guide is agricultural-focused and it helps one get as self-sufficient as possible.
Tappan On Survival, by Mel Tappan. This is classic guide to getting started with preparedness.
Survival Guns, by Mel Tappan. This is a large text that covers all facets of firearms for survival. Some of it is quite dated, but its still a good text.
Nuclear War Survival Skills, by Dr. Edward Teller is, as the name implies, focused on nuclear war survival, but it does address long term situations. Its also available free
here.
Shoestring Survivalism, by Andy James. This is another getting started guide that focuses on getting ready on a budget.
Regarding military manuals ...
FM 21-76 US Army Survival ManualThe SAS Survival Handbook, by John Wiseman
Hope that helps with your research.