William Sheehan is an amateur astronomer (and professionally, a neuroscientist and psychiatrist specializing in neurodevelopment and brain imaging). He has written Planets and Perception (an Astronomical Society of the Pacific Book of the Year, 1988), The Planet Mars (a book-of-the-month club selection in 1996), and Mars: the lure of the red planet (with Stephen James O’Meara), among many other books. In 2004, Sheehan was awarded the Gold Medal of the Oriental Astronomical Society for his Mars studies; he was the first Caucasian to receive this prestigious award. He has for many years been a contributing editor of Sky & Telescope and is a research fellow of the Lowell Observatory in Flagstaff, Arizona.