Today most of us get our knowledge and information online through google, blogs, wikis, YouTube and what have you. However, in a post SHTF world, those sources may be hard too reach at best.
For example, how do you access Wikipedia without electricity, google without internet or watch videos with a dead laptop?
This is why you will want to get those articles printed and why you would want to have good old fashioned paperback books in your house or bug out location. For the cost of some toner, paper and binders, you can backup essential knowledge in case of an emergency where you either have no access to internet or no power for a long time.
Things to print or buy books on include food conservation, gardening, hunting, building, repairs and why not just “how to rebuild society”.