There is an endless supply of things that might be good to know in the event of a long term disaster, or The End Of The World As We Know It, (TEOTAWKI). In the time we have left before something like this happens to us, we can't possibly learn everything we might like to know.
I have suggested Maslow's Hierarchy of Needs as a starting place to decide what order to work on your preparedness. It is not the only way to go about it, and not everyone agrees with him on what order to place our needs. Even so, Maslow's Hierarchy of Needs gives you someplace to start. You can always rearrange or add things to suit yourself.
Once you decide what you need to learn most, you can start learning or even getting books or materials to allow you to learn less immediate needs after TEOTAWKI.
I must remind you, (and myself,) that it is easier to carry more inside your head than on your back. If you have to bug out or evacuate, you probably will not be able to carry a very large library. If you have a Bug Out Location, you will probably want to have an adequate library, but you have to leave room for other things, including yourself.
The endless nature of good things to know for TEOTAWKI can make your library a financial problem. That is why I found lots of nice places to get free information to use for preparedness.
The most recent one that I am enjoying is Amazon Kindle Books. You do not have to invest in a Kindle to read their books. You can download different free versions of software that will allow you to read Kindle books on a PC, an Apple, an ipod, etc.
I got the PC version, and I love it. Amazon has a large library of preparedness books that you can download for free. Below is a link to download the app for reading Kindle on your PC. Don't worry if you don't have a PC. All of the other downloads for other ways to read Kindle books are there too. http://www.amazon.com/gp/feature.html/ref=amb_link_357628962_11?ie=UTF8&docId=1000426311&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=left-1&pf_rd_r=1QAPDAK4CVRKFB4HDYWD&pf_rd_t=101&pf_rd_p=1364551862&pf_rd_i=133141011
Here is another link to Kindle and links to free book collections. Some of the other libraries besides Kindle's own, may cost you something to access through Kindle. I believe you can go to some of the sites and download their own reader software and avoid charges. Please check this to make sure.
There is one disadvantage of Kindle free books. You do not get to keep them forever. They go away after a while. You also agree not to print them out when you receive them from Kindle.
There are ways to avoid paying for a Kindle free book if you decide that you want to keep it. Many of them come from sites that offer them for free. The conditions for downloading or printing the book may be less restrictive than Kindle's. They may give you permission to print, pass them on to others, or save them permanently in a digital format.
If you live in a country besides the USA, it may cost you to download books, including Kindle. If that is the case, you may be able to avoid this by getting free books from Google.