considerable energy has been spent in presenting the material in a reader-friendly, conv- sational style. And as before, the book remains firmly rooted in physiology. My thanks are due to Madhu Reddy, Director of Universities Press ¿ formerly a professional associate and now a friend, P. Sudhir, my tireless Pulmonary Function Lab technician who found the time to type the bits and pieces of this manuscript in between patients, A. Sobha for superbly organizing my time, Grant Weston and Cate Rogers at Springer, London, Balasaraswathi Jayakumar at Spi, India for her tremendous support, and to Dr. C. Eshwar Prasad, who, for his words of advice, I should have thanked years ago. vii viii Preface to the Second Edition Above all, I thank my wife and daughters, for understanding.