"In a civilization based on exchange and consumption, rather than on work and contemplation, everything is reduced to a problem to be solved. Preferably, the solution should involve the making and sale of products and services. Yet every solution creates another problem, because in truth, both the air and the rest of us are not problems to be solved but mysteries in which we live. Mysteries, as the French existentialist Gabriel Marcel knew, are not matters that are beyond us. They are matters that envelop us.

"The air is the archetype of such a mystery. In this book, I propose that we get to know it not only as a problem, but also as a wonder. We will discover the air by means of what happens in it and through it.

"The air is never empty, although mostly it seems to be. Floating invisible through it are gases, dust, fungi and bacteria, pollen, and liquid and solid particles called aerosols. Unseen though they may be, each plays its part in the concert of the world. Some decay the dead, some make rain fall and bring increase, some promote health or seed disease.

"The air is spinning. All the phenomena of weather and climate come from the restless motions of the air, the gyres, and all their permutations that bring rain, snow, fog, hail, sleet, black ice, tornadoes, hurricanes, the layers and the heaps of the clouds, the rising smoke of the chimneys. We can't control the weather, but nevertheless the weather changes as we change the contents of the air.

"The air is the medium of flight. It is a remarkable thing that solid objects leave the ground, but they do. Leaves, bits of bark, candy wrappers, airplanes, birds, insects or bats, all are translated through the air through the law of wings.

"All creatures tell each other stories and call to one another through the medium of the air. Sometimes the telling is by chemical signals, by odors, scents, perfumes, stenches. Sometimes, the calling is by means of waves that travel through it — compressing and expanding the front of the air — to make the range of sounds, their harmonies and discords.

"All that is alive exchanges gases with the air by means of the phenomenon of breath, and whatever we breathe out is breathed in by some other living thing. The energy to live is derived from these exchanges in the air.

"Finally, the shining of the sun in the atmosphere brings color to the sky and to the world. In outer space, only objects have a color. All else is black. On this earth, we live in a world of shifting colors, lights and shadows, by means of the slow cold flame of the sky."