Raymond C. Valentine is currently professor emeritus at the University of California, Davis and visiting scholar in the Marine Science Institute at the University of California, Santa Barbara. He was also the scientific founder of Calgene, Inc. (Davis, California), now a campus of Monsanto, Inc. The author’s scientific interests involve the use of reductionism to address problems of fundamental scientific and societal importance, such as agricultural productivity and aging. Some of his scientific accomplishments include the discovery of ferredoxin, the identification and naming of the nitrogen fixation (nif) genes, and the development of Roundup® resistance in crops. He holds BS and PhD degrees from the University of Illinois at Urbana-Champaign. David L. Valentine is currently a 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, his works on archaeal metabolism and ecology, and his scientific work on the Deepwater Horizon oil spill. DLV holds BS and MS degrees from the University of California at San Diego and MS and PhD degrees from the University of California at Irvine.