Zombies are either infected living humans or voodoo spell victims that feed on human flesh. The document outlines how the zombie virus spreads and kills its host before reanimation. It describes zombie characteristics like sluggish movement and gray skin. Effective defenses include weapons, armor, securing defensible locations, traveling on foot or small vehicles, staying quiet and alert, and organizing supplies. Even after zombies die off, the post-apocalyptic environment remains dangerous. Proper preparation and following survival tips can help defend against zombie invasions.