Everette Lee DeGolyer wore many hats-and he wore them with distinction. Though not a geophysicist, he helped make geophysics central to oil exploration. Though not a politician, he played an important role in the national politics of energy. Though trained as a geologist, he became an important business executive. DeGolyer left his stamp on oil exploration and his name on a number of philanthropic institutions, including the DeGolyer Library at Southern Methodist University.This account of DeGolyer's life, at once readable and yet authoritative, covers the period from his training with the United States Geological Survey in the American West, to his geological exploration of Mexico during the Revolution of the 1910s, his pioneering investment in geophysical prospecting technologies, and his work on behalf of the United States government in World War II, including a ground-breaking secret mission to the Middle East. Houston Mount develops his account of the career of Everette Lee DeGolyer in a way that provides a useful lens through which to examine the rising fortunes of earth scientists in the oil industry and in government-a process for which DeGolyer's spectacular career was both an exemplar and a catalyst.