Advances in Aeronautical Sciences, Volume 3 contains the proceedings of the Second International Congress in the Aeronautical Sciences held in Zurich, Switzerland, on September 12-16, 1960. The papers explore advances in aeronautical sciences and cover topics ranging from the role of entropy in the aerospace sciences to the theory of hypersonic flow over blunt-nosed slender bodies. The effect of boundary layer transition at the leading edge of thin wings on general nose separation is also discussed, along with the aerodynamics of aircraft shapes for flight at supersonic speeds. This book is comprised of 28 chapters and begins with a review of the importance of entropy in the aerospace sciences, citing the work of Nicolaus Sadi Carnot and Rudolf Clausius as well as enthalpy and free enthalpy. The link between entropy and molecular theory is also described before turning to the physics of jet streams and the aerodynamics of jet flaps. Other chapters consider a wide range of problems both of theoretical and practical importance, including the flow around a circular cylinder; the theory of boundary layer; the physics of transition from laminar to turbulent flow; and the theory and experimental knowledge of transonic, supersonic, and hypersonic flows. Due attention is given to the re-entry of missiles and space vehicles into the atmosphere; problems of trajectories; guidance of space vehicles; and power generation in space. The economic and technical aspects of air transportation are also highlighted. This volume will be of interest to scientists and engineers in aeronautics and astronautics.