A renegade team of scientists discovers the truth behind the Oracle of Delphi's mythical powers of second sight. Of all the stories of life in ancient Greece, few capture the imagination as much as the Oracle of Delphi. Human mistress of the great god Apollo, the Oracle had the power to enter into ecstatic union with him and bring back his prophecies and counsel for all who came seeking answers. Residing in her temple on the sacred slopes of Mount Parnassos in central Greece, she was consulted on matters large and small. Though the air of magic that surrounds her might cast her as a legend, the Oracle did really exist-and her visions caused her to become the single most influential figure in all of ancient Greece. Eyewitness accounts from Plutarch and others describe temple practices in astonishing detail, claiming that the Oracle, in preparing to commune with Apollo, breathed in vapors rising from the temple floor. Modern scholars have had rigorous debates about the reliability of the material, and in 1892 French archaeologists unearthed the buried temple itself. Their guide was the ancient literature, which proved to be remarkably accurate, with one glaring, baffling exception-the excavators could find no hint of a chasm beneath the temple, no evidence that the rocky ground had brought vapors of any kind. There followed nearly a century of scholarly denouncement. Critics dismissed not only reports of intoxicating fumes but the Oracle herself, claiming the evidence suggested that she and her minions were nothing but pious frauds. Then a Wesleyan geologist named Joelle deBoer and a young archaeologist, John Hale, decided to take up the question once more. Pulitzer Prize-winning journalist and bestselling author William J. Broad tells a modern-day detective story that blends history and science to describe how a team of scientists, working from subtle clues scattered throughout the ancient literature, as well as from the latest findings in geology, uncovered scientific evidence to explain the Oracle's powers. They discovered that the vapors from the ancient accounts were, in fact, petrochemical fumes containing a hallucinogenic gas, rising through natural faults hidden underneath the temple floor. Into the dramatic account of that groundbreaking discovery Broad weaves the fascinating story of the ancient Oracle, and her surprising power to open a modern debate between science and religion.