It is a big book because it has the whole realm of the sky to range over, from the heavy lower depths where man first tried his wings, where wind and cloud form the ever changing patterns of weather, out through the upper reaches of the stratosphere which only jets and rockets can probe, to the airless heights of the ionosphere (the unexplored no man's land between earth and outer space).

We have already grown so accustomed to our new wings that we forget how miraculous is each transatlantic flight. To find his path in the trackless night skies man has had to harness not only the stars, but the infinitely useful radio waves and the magic forces of the earth itself. He has had to explore the mighty currents of air that carry with them the breath of the seasons, the rain and snow, the restless calms and lashing tempests.

To unlock the secret of flight he had to understand the capricious ways of this air, he unseen sticky substance that flows about us, nourishing life and supporting the dying features as the seas support those that swim.

The history of this search for knowledge of the skies and an explanation of what we now know form the basis of this book. Mr. Murchie deals with many technical matters of meteorology and aerodynamics but the force of his imagination and the poetic sweep of his prose give his story meaning for both professional flyers and groundlings as it unfolds the wonders of the sky.

If some of the facts here presented seem fanciful, it is because nature aloft as Mr. Murchie found it does not conform to standard textbooks. Yet his work checks with the pioneers who are gathering the amazing new material that will be the foundation of the textbooks of the future. And behind every chapter lie years of actual flying experience, including a share in pioneering the North Atlantic ocean of the sky in its first year of regular scheduled flight, just one decade ago this year.