Your smartphone, the weather forecast you checked this morning, and the doctrine of mutually assured destruction all trace back to one mind. John von Neumann mastered calculus at eight, memorized phone book pages as a party trick, computed ten times faster than Nobel laureate Enrico Fermi, and mathematically proved self-replicating machines were possible before biology had even found the double helix.

This episode maps the architecture of that brain: the fly puzzle he solved by instantly summing the infinite series, the Hilbert space framework that unified quantum mechanics' warring mathematics, and the surprising self-doubt of a man who feared he lacked Einstein's intuition. It follows him through the Manhattan Project and game theory to the stored-program computer, cellular automata, early climate-change warnings, and the term he coined:  ...