This week, we're digging into a tale of intrigue that may have changed the course of physics research in the 20th century. We'll spend the hour with Frank Close, Professor of Physics at the University of Oxford and Fellow of Exeter College, Oxford, talking about his book "Half-Life: The Divided Life of Bruno Pontecorvo, Physicist or Spy." We'll learn about Pontecorvo's groundbreaking career in particle physics, his defection to the Soviet Union, and the accusations that he traded nuclear secrets at the height of the Cold War.