Tuberculosis - the greatest killer of all time - has claimed more than a billion lives worldwide. Dr. Frank Ryan tells the remarkable story of the handful of dedicated doctors, chemists and bacteriologists who searched for and found a cure for this ferocious disease - an extraordinary detective feat that owed as much to luck and intuition as to any systematic scientific process. But a story that once ended in triumph now carries a dire warning, for the "old enemy" has found a new ally - AIDS - creating a deadly drug-resistant synergy that is ravaging the globe. As we face one of the worst epidemics of all time, no story could be more relevant.