Keven tells you nothing in his book, he wants you to spend money and join his website, etc., so he can tell you his secrets. I think his ancestors sold snake oil of the back of a covered wagon.
I grew up in the woods, and I would just as soon carry my chewing gum, snacks, firestarter, aspirin, etc. with me. You will eventually get something wrong 8^).
Patrick F. McManus, describing old Rancid Crabtree, said Rancid was showing him edible plants, etc. Rancid grabbed a hand full of greens and said, "Ever eat miner's lettuce boy?"
He stuffed it in his mouth and started chewing....then started gagging and spit it out. Then said, "Well that aint it boy....don't ever eat anything that looks like that!"
Rancid was quite a woodsman.