Almost everyone has had the experience of smelling something in the air and being vividly reminded of another time or place where that particular scent was present. This "associative" or evocative nature of fragrance has its roots in the structure of the body itself. The sense of smell differs from the other major senses in that it's more primitive, working more directly with that part of the brain which is "older," in an evolutionary sense, than the rest of the brain.
The smell of bread rising - a heady, yeasty smell - may bring back moments spent in the kitchen during childhood, together with intense recollections of how the kitchen looks, who you were with or what people said many years ago. In exactly the same manner, the fragance of incense - carried through the air - may inspire thoughts or feelings, setting the mind at rest and into a receptiveness for images of all kinds. It is for this reason incense has been used for thousands of years in conjunction with meditation and prayer. And, needless to say, for the same reason, incense has been used to eliminate or camouflage other odors which are offensive, which may evoke unpleasant assocations.
Incense is unlike other kinds of perfumes because it is designed to spread fragrance to its target immediately, creating an atmosphere or setting a tranquil pace for whatever activity is intended. It is also infinitely more versatile than other perfumes, because it goes far beyond being just a perfume. Good incense makes use of substances like tree barks and saps, roots, flowers and other botanical products, which cannot be liquefied or isolated into a perfume or cologne. And, in the burning, ingredients of extremely differing forms combine into a single, unique bouquet containing subtle tones or shadings.
Incense is a kind of "mental stimulant" which can transform the ordinary into the very special, and do so easily at no great expense. Fine incense burning in a plain room with gental lighting and a few special mementos can produce a setting which subtly calls the psyche to relax, lighten and allow flow with the moment. Whether the space is a temple or a bedroom, the effect is the same. A mood is set and the moment takes on a heightened, special meaning.