Bruce StephensonBruce Stephenson is Curator and Director of the History of Astronomy Department at Chicago's Adler Planetarium & Astronomy Museum. He received his Ph.D. in History from the University of Chicago, where he holds a position of visiting scholar in the Dpartment of Astronomy and Astrophysics. He is the author of Kepler's Physical Astronomy and of The Music of the Heavens: Kepler's Harmonic Astronomy, both published by Princeton University Press. He belongs to numerous professional organizations relating to the history of science, astronomy and scientific instrumentation. He is currently studying the metallurgical characteristics of astrolabes in a high-energy X-ray beam at the Advanced Photon Source at Argonne National Laboratory. Read More Read Less