Bill and Gayle Hartmann (here seen in Oct. 1997). Bill received a B.S. in physics from the University of Pennsylvania and then moved to Tucson to become a student and work in GP Kuiper's Lunar and Planetary Laboratory. He earned a MS in Geology and a PhD in Planetary Astronomy at the University of Arizona; he is currently a senior scientist at the Planetary Science Institute in Tucson. Bill was the first person to map the concentric and radial structures of impact basins. He also used the crater counts from DWG Arthur's lunar crater cataloging group to deduce the correct age of the lunar maria. Bill is a prolific space artist and author of textbooks and novels. Gayle is an archeologist and active environmentalist.