My newest column for Discover is about that strangest of the senses, smell. An odor can be an overwhelming experience, and yet it's often impossible to put that experience into words. In fact, we're terrible at naming smells, despite being exquisitely sensitive to the differences between them. I take a look at some recent research that may bring us closer to resolving this paradox, with the invention of the first yardstick for the nose--a simple measurement of odor molecules that reveals a lot about how pleasant or vile we find them. Not only might it help us understand our own noses, but it may even let us build electronic noses to sniff for things we don't want to stick our own noses in. Check it out.