Sir Mark Oliphant hasn't had a billion-dollar movie made about him, but — according to the author Roland Perry — maybe he should have. Oliphant was an Australian physicist who played a crucial role in convincing Oppenheimer and the Americans that a nuclear bomb was possible, and necessary. Without Oliphant, Perry says, it's possible the Germans would have built the bomb first.

• Guest: Roland Perry, author of more than 40 books
• Producer: Alex Tighe