Bill Melson is geologist emeritus at the Smithsonian’s Museum of Natural History, Washington, D.C., where he has led geology tours to the Appalachians for the Smithsonian Associates and other organizations for the past forty years. Melson received geology degrees from Johns Hopkins University (BA) and Princeton University (PhD) and is a fellow of the Geological Society of America and the Mineralogical Society of America. With Brian Mason, he wrote the first textbook on The Lunar Rocks (Wiley and Sons) and served on NASA’s Apollo 14 Preliminary Examination team. His writings include chapters in the Smithsonian’s Book of the American Land (Shenandoah Roots) and in the Smithsonian-National Geographic book Forces of Change (Global Synergies). The ongoing eruptions of Arenal Volcano, Costa Rica, are a major subject of his current research. Melson has worked in archaeology with Dr. Richard Potts on the origin of fused zones within the sediments at the Homo erectus site at Olorgesalie, Kenya.