The Fifty-Eighth Wilbur and Orville Wright Memorial Lecture was given by Dr. S. G. Hooker at the Royal Aeronautical Society on 4th December 1969. The chair was taken by the President of the Society, Air Commodore F. R. Banks. Following custom, the Society's honours and awards for the year were presented before the Lecture. These are listed, with their citations at the end of this lecture.On 3rd December 1903, with the wind gusting up to 25 mph (11·2 m/s), Orville Wright staggered into the air in a flimsy aeroplane powered by a four-cylinder piston engine, and, with that event, the Wright Brothers had added a new dimension to man's ability to travel (Fig. 1).Their success was not just a piece of luck, but the result of years of study and experimentation, coupled with great personal effort in the design and manufacture of their aircraft. Like all pioneers, they were faced with important gaps in the availability of suitable equipment, particularly an engine of sufficient power and light enough in weight, and a propeller of high enough efficiency. These they had to develop for themselves.