ETHIRAJAN RATHAKRISHNAN, Ph.D., is Professor of Aerospace Engineering at the Indian Institute of Technology Kanpur. He is well known internationally for his research in the area of high-speed jets. The limit for the passive control of jets, called Rathakrishnan Limit, is his contribution to the field of jet research. The concept of breathing blunt nose (BBN), which reduces the positive pressure at the nose and increases the low pressure at the base simultaneously, is his contribution to drag reduction at hypersonic speeds. He has published a large number of research articles in many reputed international journals. He is a Fellow of many professional societies, including the Royal Aeronautical Society. Professor Rathakrishnan serves as the Editor-in-Chief of the International Review of Aerospace Engineering (IREASE) journal. He has authored eight other books.