He owned no home, paid no rent, and lived out of a single suitcase for over 50 years, relying on a global network of colleagues to feed him, do his laundry, and arrange his travel. Yet Paul Erdos became arguably the most prolific producer of mathematical knowledge in history.

This episode explores how a sheltered, tragedy-shaped childhood produced an intellectual nomad who turned a solitary pursuit into a globe-spanning social activity. From his invented vocabulary and his run-in with the FBI to his amphetamine-fueled output and the legendary Erdos number, we ask whether his life was a tragedy of isolation or the ultimate triumph of pure discovery.

• A grief-stricken, overprotected childhood that he later "optimized" into perpetual motion
• His private language: epsilons for children, the Supreme Fascist, and "this one's from ...