Andrew H. Knoll is the Fisher Professor of Natural History at Harvard University. His honors include the International Prize for Biology, the Charles Doolittle Walcott and the Mary Clark Thompson Medals of the National Academy of Sciences, the Paleontological Society Medal, and the Wollaston Medal of the Geological Society of London. For nearly two decades he served on the science team for NASA's Mars Exploration Rover mission. Knoll is also the author of Life on a Young Planet, for which he received the Phi Beta Kappa Book Award in Science.