This Nuclear Survival Manual written by James R. Fairlamb will tell you everything you need to know about how to prepare for and survive a nuclear blast.

It also explains how to build a BOSDEC (Bomb Shelter in Depth Concept)

This tool allows you to download all of Wikipedia and view the articles and pictures offline.
Most preps are practical or skill based. But what if you need to know something? Think of how many times what you are looking for takes you to Wikipedia.