Highly compressed Offline wikipedia and other wikis
http://www.kiwix.org/wiki/Main_Page
Also, what else should be stored or installed in a laptop, tablet or other computer?
I have some books dealing with stuff such as farming, medicine, pharmacology (mostly medicinal plants and other easy to obtain substances), guerrilla warfare, physical training, water procurement and filtration and a few other things I can't remember off the top of my head.
The main problems are that they are a bit disorganized and of varying quality and up-to-date-ness.