In 1950, at the dawn of the Cold War, Italian physicist Bruno Pontecorvo mysteriously disappeared, sending shockwaves through the political world. Bruno Pontecorvo’s disappearance remains one of the greatest mysteries of the atomic age, especially since it was later discovered that the Italian scientist had crossed the Iron Curtain to settle in the Soviet Union. Bruno Pontecorvo was also the scientist who succeeded in unraveling the secrets of the most elusive and enigmatic particle in the universe, the neutrino.