A must-read for anyone interested in the history of modern medicine, Rooke masterfully weaves together the life stories of characters as disparate as John F. Kennedy, Ernest Hemingway, Thomas Addison, and Nobel laureates in physics and medicine to tell the compelling story of how scientific progress is truly made, with a particular focus on the development of cortisone and related steroid therapeutics. Far from the “neat and tidy,” inexorable, and logical process most readers may assume underlie scientific breakthroughs, the reader will learn of the protagonists’ flashes of brilliance, but also of their mistakes, losses, and many disappointments overcome through bull-headed perseverance, hard work, and team work. I couldn’t put it down. —David M. Harlan, Chief of Diabetes Division and Co-Director of the Diabetes Center of Excellence, UMass Memorial Health Care; William and Doris Krupp Professor of Medicine, University of Massachusetts Medical School