Many of these foods are simple meals that require you to add water and heat (such as MRE's, or Meals Ready to Eat). However, if you buy individual bulk ingredients you can create more of a gourmet pantry which allows you a much greater range of meals to prepare—powdered eggs, spices, all sorts of flours, honey, etc. These foods are not only great for food storage but also for camping trips, especially if your camp kitchen is serving a large crowd.
Though its light weight and long shelf life are ideal for navigating harsh conditions, freeze-dried food is probably most famous as a cultural curiosity: Like many Americans, I discovered it in a museum gift shop, gawking at the styrofoam-like ice cream that astronauts used to have for dessert. More recently, I encountered it at a disaster preparedness convention in Raleigh, North Carolina, where smiling, gray-haired preppers manned tables piled with plastic bags full of vegetables, meats, and stews.