Theory predicts that when people pursue their selfish aims then it leads to suboptimal outcomes for society or to the group they belong to. The prisoner's dilemma and the tragedy of the commons are classic examples. In her presidential lecture to the American Political Science Association Elinor Ostrom examined this fact and also noted that in practice people do not always follow the suboptimal strategy. What does she suggest? This document consists of slides I created giving an account of her paper. She had not won the Nobel when she gave this talk but it was conferred on her later.