Nose dive : a field guide to the world's smells
"Smell is such a powerful and revealing sense because it detects actual little pieces of things in the world. It gives us direct evidence of what those things are made of-unlike the indirectness of vision or hearing, which register light waves and air movements. Those little pieces are volatile molecules, so little that they're able to break away from their source and fly invisibly through the air to reach our nose. To begin to understand a thing...