Of all our senses, the sense of smell is probably the least studied and appreciated. However, in recent years our scientific understanding of how we perceive scents and what they do to our brains and immune systems has deepened. It turns out that scent accounts for around 80% of the experience of flavor, a dominant force in the experience and enjoyment of eating. We also are learning how scents clearly and directly affect our emotions. Some scents (even when you hardly perceive them) will pick you up and give you energy while others will help calm you down or take you to a remembered experience. Our deepening understanding has reached the point where a new wave of technologies is being developed by a new crop of startup companies that promise to make an impact on a range of industries from food and restaurants to health and wellness.