In 1948, when “Mrs. G.,” hospitalized with debilitating rheumatoid arthritis, became the first person to receive a mysterious new compound—cortisone—her physicians were awestruck by her transformation from enervated to energized. After eighteen years of biochemical research, the most intensively hunted biological agent of all time had finally been isolated, identified, synthesized, and put to the test. And it worked. But the discovery of a long-sought “magic bullet” came at an unanticipated cost in the form of strange side effects. This fascinating history recounts the discovery of cortisone and pulls the curtain back on the peculiar cast of characters responsible for its advent, including two enigmatic scientists, Edward Kendall and Philip Hench, who went on to receive the Nobel Prize. The book also explores the key role the Mayo Clinic played in fostering cortisone’s development, and looks at drugs that owe their heritage to the so-called “King of Steroids.”