Dr. Gary Prost obtained a BSc in Geology from Northern Arizona University in 1973 and a MSc (1975) and PhD (1986) in Geology at Colorado School of Mines. Over the past 38 years Dr. Prost has worked for Norandex (mineral exploration), Shell U.S.A. (pertroleum exploration world-wide), the U.S. Geological Survey (geologic mapping, coal), The Superior Oil Company (mineral and oil exploration), Amoco Production Company (world-wide oil exploration), Gulf Canada (international new ventures) and ConocoPhillips Canada (Canadian Arctic exploration, field development, oil sands modeling and reservoir characterization). Dr. Prost spent over 20 years working as an image analyst/photointerpreter in the search for oil and minerals in over 30 countries. During this time he applied remote sensing in exploration, mineral and oil development projects, and environmental monitoring. Dr. Prost is the principle in Prost and Associates, consultants on geologic exploration and development projects and applies the most recent technologies to his work. Benjamin P. Prost (coauthor) has had an interest in geology since he tried to eat a sample of native sulfur in his parents’ backyard. He was 3 years old, and the yellow crystals were appetizingly orthorhombic. The son of a geologist, he could identify pyrite, galena, gypsum, and several other minerals before he knew the alphabet. A bit later, he graduated from Occidental College with a degree in something other than geology (a decision he regrets). For the past 11 years, he has been a writer, editor, grammar maven, and style-guide aficionado in Los Angeles and New York. He currently writes and edits online children’s books. He is valued for his ability to limn scientific topics in language that any first grader can understand—which is much harder than it sounds. He is routinely called upon by coworkers to explain the difference between weathering and erosion.