This introduction to rotorcraft and their technology begins with a broad review of several types of rotorcraft.The evolution of these unique aircraft,from autogyros to helicopters to high-speed configurations,has spawned a major industry and an associated technology.The history of rotorcraft, beginning with very early concepts and modelhelicopters,has been well recorded in the popular literature.On the other hand,the evolutionof the technology resides in literally thousands of technical publications. I have tried to bring together the popular history of rotorcraft evolution and the parallel,major technical steps made by its pioneers.Tying the engineering explanations andanalyses to configuration evolution provides the reader with two foundations. The firstfoundation is a more complete appreciation of what has been accomplished in