Card 1 of 8: Nash Equilibrium
Nash proved it in one page in 1950: every game has at least one point where nobody can do better by switching strategy alone. That point isn't necessarily the best outcome for anyone — just the one nobody can unilaterally escape.
Two RAND researchers stumbled into game theory's most famous parable in 1950, later christened the prisoner's dilemma — showing rational self-interest can trap two people in a worse outcome than cooperation.
Most decisions that matter aren't made in isolation — they're made against other people who are also deciding. Game theory is the formal language for that situation.
Axelrod ran a computer Olympics for prisoner's dilemmas in 1980: every submitted strategy played every other for 200 rounds. The winner was four lines long.
Zahavi watched Arabian babblers make extravagant, dangerous displays to signal status — wasting energy precisely to prove they could afford to waste it.
Russell used Chicken — two cars racing toward each other, first to swerve loses — as a metaphor for nuclear crisis. Schelling turned it into the doctrine of brinkmanship: deliberately approach the brink to force the other side to back down.
Hurwicz asked the inverse question of game theory: don't predict how people will play this game — design a game people will play truthfully even while pursuing self-interest.
In 1944 von Neumann and Morgenstern formalized games where the chips on the table never change: poker hands, fixed-budget negotiations, and wars for territory are zero-sum; trade, innovation, and trust-building are not.