Dr. Sheehan is a practicing psychiatrist, amateur astronomer, experienced Mars observer, a contributing editor to Sky & Telescope, historian of astronomy, and first-rate author. His books include, "Planets & Perception" (1988), "Worlds in the Sky" (1992), the first biography of one of the greatest observers of all time, "The Immortal Fire Within: The Life and Work of Edward Emerson Barnard" (1995), "The Planet Mars" (1996), "In Search of Planet Vulcan" (with Richard Baum, 1997), "Epic Moon" (with T.A. Dobbins, 2001), "Mars" (with S.J. O'Meara, 2001), and "Transits of Venus" (with J. Westfall, 2004). He is currently working on a biography of W.W. Morgan. Sheehan is noted for his meticulous research and eloquent prose. His biography of Barnard is a classic.