What do we mean when we say that something smells of fresh paint? Or frying bacon? And what does five o'clock in the morning smell like? Here Barney Shaw delves into the olfactory world to discover its complexities, and finds surprising beauty in its processes. As Shaw points out, we use smells to communicate, to warn us of danger, to give us a sense of place, and as a form of social messaging, but smell has other, less obvious uses: a sniff of peppermint or even fish oil can increase alertness and productivity. Shaw's investigation into the biology, psychology and history of what the nose knows (and doesn't) also includes a 200-entry glossary that attempts to capture the essence of common smells.