The aim of this symposium was to gather fellow researchers, colleagues and friends of Professor William R. Sears, a member of the National Academy of Science and the Academy of Engineering, on the occasion of his 80th birthday. Professor Sears is a leader in aerospace science and aerodynamics research, and the symposium was held in honour of his work in these areas. The symposium focused on four areas in aeronautical science in which Professor Sears has made major contributions. These are wing design, unsteady aerodynamics and separation, aeroacoustics and self-correcting wind tunnels.