Immersed in our daily lives, we hardly notice the scents around us. We do not perceive the blooming roses, the fragrance of the pine forest, the smell of freshly cut hay, or the aroma of fruits and vegetables on our table. Yet, as soon as we focus our attention on them, we realize that we quite literally live in a sea of scents. Every day, we are confronted with hundreds, even thousands of them. There is the smell of tea, coffee, soup, gasoline, creams, perfumes, and so on. We perceive and analyze them unconsciously. Our awareness of scents becomes conscious when they are very strong, pleasant, or unpleasant, and when we focus on them.