Lon Hood received a Ph.D. in geophysics and space physics from the University of California at Los Angeles in 1979. In the following year, he joined the Lunar and Planetary Laboratory at the University of Arizona as a postdoctoral research associate. He became an assistant research scientist there in 1983 and was promoted to senior research scientist in 1995. His early work dealt mainly with lunar and planetary geophysics. In 1984, with some support from Donald Hunten, he initiated work on studies of the stratospheric response to short-term solar ultraviolet variations. With later support from NASA, DOE, and NSF, he expanded this work to include longer-term variability of the stratosphere, including that which occurs on the solar cycle time scale. During the last 10 years, he has continued working on both stratospheric physics and planetary geophysics.