David L. Valentine, Ph.D., is currently professor of earth science with affiliations in ecology, evolution, and marine biology, as well as the Marine Science Institute, at the University of California, Santa Barbara. The author’s scientific interests involve the use of a systems-based approach to investigate the interaction between microbes and the Earth, particularly in the subsurface and oceanic realms. He is best known for his research on the biogeochemistry of methane and other hydrocarbons, for his works on archaeal metabolism and ecology, and his scientific work on the Deepwater Horizon oil spill. Dr. Valentine holds B.S. and M.S. degrees from the University of California at San Diego and M.S. and Ph.D. degrees from the University of California at Irvine.