PREFACE
Airplane photography had its birth, and passed through a period of feverish development, in the Great War. Prob- ably to many minds it figures as a purely military activity. Such need not be the case, for the application of aerial photography to mapping and other peace-time problems promises soon to quite overshadow its military origin. It has therefore been the writer's endeavor to treat the sub- ject as far as possible as a problem of scientific photog- raphy, emphasizing those general principles which will apply no matter what may be the purpose of making photo- graphs from the air. It is of course inevitable that who- ever at the present time attempts a treatise on this newest kind of photography must draw much of his material from war-time experience. If, for this reason, the problems and illustrations of this book are predominantly military, it may be remembered that the demands of war are far more severe than those of peace; and hence the presumption is that an account of how photography has been made suc- cessful in the military plane will serve as an excellent guide to meeting the peace-time problems of the near future.
It is assumed that the reader is already fairly conversant with ordinary photography. Considerable space has indeed been devoted to a discussion of the fundamentals of photog- raphy, and to scientific methods of study, test, and speci- fication. This has been done because aerial photography strains to the utmost the capacity of the photographic process, and it is necessary that the most advanced methods be understood by those who would secure the best results or contribute to future progress. No pretence is made that7
