The conquest of the sea can never be recorded in history; even the conquest of the air, which was achieved within the lifetime of all but the very youngest of those who are now alive, admits of no sure or perfect record. The men who bore a part in it, and still survive, are preoccupied with the future, and are most of them impatient of their own past. Where knowledge begins, there begin also conflicting testimonies and competing claims. It is no part of the business of this history of the war in the air to compare these testimonies or to resolve these claims. To narrate how man learned to fly would demand a whole treatise, and the part of the history which ends in December 1903 is the most difficult and uncertain part of all. Yet the broad outlines of the process can be sketched and determined. It is a long story of legends and dreams, theories and fancies, all suddenly transformed into facts; a tale of the hopes of madmen suddenly recognized as reasonable ambitions. When in the light of the present we look back on the past our eyes are opened, and we see many things that were invisible to contemporaries. We are able, for the first time, to pay homage to the pioneers, who saw the promised kingdom, but did not enter it. No place has hitherto been found for their names in serious history. _The Dictionary of National Biography_, with its supplement, includes the lives of all the famous men of this nation who died before King George the Fifth was king. Yet it contains no mention of Sir George Cayley, the Father of British Aeronautics; nor of John Stringfellow, who, in 1848, constructed the first engine-driven aeroplane that ever flew through the air; nor of Francis Herbert Wenham, whose classic treatise on Aerial Locomotion, read at the first meeting of the Aeronautical Society, in 1866, expounds almost every principle on which modern aviation is founded; nor of James Glaisher, who, in 1862; made the highest recorded balloon ascent; nor of Percy Sinclair Pilcher, who lost his life in experimenting with one of his own gliders in 1899. These men attracted little enough notice in their own day, and were regarded as amiable eccentrics; but they all thought long and hard on aerial navigation, and step by step, at their own costs, they brought it nearer to accomplishment.