Euell Gibbons wrote 4 books for preppers. (wild, home)

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2 on edible wild plants (to include their caloric value and how to prep for eating and preservation). He also wrote a book about beachcombing and another about wild plants as condiments. He was smart enough to learn the conditions each plant favored. Then he'd either transplant them or take the seeds and plant them MUCH closer to his home than where he'd originally found them. :-)