Great Wilderness Survival Skill - Flint Knapping
Generally, I never go anywhere without a multitool and at least one sharp liner-lock or lock-back knife. If I plan on heading outdoors for a leisurely trip, I'll add a razor-sharp 440C steel full-tang fixed blade. For any extended outdoors stay, or if I anticipate any threats, I'm bringing an axe. I actually have several knives and an axe in my car, so they're often very accessible. However, you can't always take for granted that they won't break, won't get lost, won't sink to the bottom of a lake, or they'll be there when you need them. That's why my survival camp counselor, Roger "Hawkman" Tucker, insisted we learn flint knapping.
Flint knapping is the skill of taking stones or glass, and creating sharpened or shaped tools from them. Evidence of flint knapping, from as far back as 4 million years ago, still exist today. In essence, it's a process of chipping and flaking off pieces of hard stones and glass into a shape you desire. Depending on the materials and your skill level, you can develop stunningly-sharp and sturdy tools that equal - sometimes surpass (obsidian knives are among the sharpest in the world, some with straight edges only 3nm wide) - the quality of modern forged tools. Not limited to just axes, arrowheads, knives, chisels and wedges, some skilled flint-knappers can craft hooks, saws, needles, sculptures, jewelry and more.
A good online guide for learning and refining flint knapping skills (along with other great wilderness survival skills) is Wyatt R. Knapp's Primitive Technology Page.