There are good reasons why carbon fiber has emerged as the king of structural material. It's supremely light, can be incredibly stiff and strong, and it can also be formed into wild shapes that simple aren't possible with metals. But it's also a multi-layered material, and only the outer surface is visible. What's underneath there? And should we care? US technical editor James Huang peels back the proverbial onion with HIA Velo senior composites engineer Chris Meertens and Australian carbon fiber repair and inspection guru Raoul Leuscher to see what's really inside.