Here’s a primer at Summit Journal.

Ever wonder why you’re still moist despite having shelled out extra money for Gore-Tex “breathable waterproof” stuff? It’s in there too. I’ve become extremely jaded about all these high-tech fabrics. Last weekend, when I hiked 9 miles in a light rain, I got back to the parking lot with water swishing in my Gore-Tex lined boots — I’m guessing the water poured onto the tongues of the boots via my allegedly waterproof eVENT gaiters and sneaked in around the stitching.