People living together must find some way to preserve common resources. Unfortunately, there are strong incentives for people to exploit these resources when they are held in common by everyone. As Prof. Sean Mulholland at Stonehill College explains, the 'tragedy of the commons' occurs when individuals acting independently end up depleting shared resources, such as fisheries or pastureland. Prof. Mullholland discusses two potential solutions to this problem: public ownership, where the property is owned and administered by the government, and private ownership. He discusses the strengths and weaknesses to each approach and some key considerations for determining which institutions best protect useful resources.