During the twelve years that the author specialized on aerodynamics, many experiments were made to test various theories, and a considerable number of mathematical formulas were developed by him to explain phenomena as observed in research and flight tests. The results have appeared in more than seventy-five publications (listed in the Appendix of this volume). These many separate papers were written without a uniform viewpoint, and the earlier papers lacked the benefit of important data that developed later, consequently it now seems advisable to present the most useful portions of that extensive material for publication as a coordinated volume.