It is now 150 years ago, on 25th May 1842, that the son of a Salzburg ston emason presented a scientific work "On the coloured light of the double stars and certain other heavenly bodies" at a meeting of the Royal Bo hemian Society of Sciences held in Prague. Christian Andreas Doppler, then professor at the Prague Technical Institute, set a milestone in scien tific history in the meeting room of the Royal Society in the Charles Uni versity, just a few meters from the National Theatre where another genius from Salzburg, Wolfgang Amadeus Mozart, had celebrated his musical triumph with the premiere of his opera Don Giovanni fifty-five years earlier. Doppler's lecture set out in brilliant simplicity what we now call the Doppler principle, which since has found numerous uses in astronomy, which was of primary interest to Christian Doppler. In addition, it has found countless practical applications in physics, navigation, aeronautics, geodesy, medicine, science and technology. In medicine alone, Doppler sonography is now an established diagnostic procedure in the fields of childbirth, cardiology and diseases of the blood vessels, neurology, neuro surgery and vascular surgery, and is continually finding new medical appli cations in today's world of high technology."

The Doppler principle is widely applied in astronomy, navigation, geodesy and a number of other disciplines of science and technology. Doppler sonography plays an increasingly important role in many fields of medicine - angiology, neurology, cardiology - an promises many exciting possibilities in the future. Yet, until recently, very little was known about the Austrian scientist whose name has been given to an established and routine medical examination. This book seeks to fill this gap and gives insight into the life of Christian Doppler, not only as a scientist, but also as a persona nd family man. It provides a wealth of new information and many new documents on the man who presented his famous paper "On the coloured light of the double stars" (which appears in facsimile with an English translation) in Prague 150 years ago this year.