Simplistic models of "the tragedy of the commons" assume privatization or centralized management are the only solutions to self-interested rational agents' over-consumption, and consequently narrow the range of available policy. The case studies presented here, covering common resources with geographic restrictions like fisheries, watersheds, and marginal forest/grazing lands, instead show that successfully managed commons (for 50 or 500 years) involve dynamic local participatory rule-making in nested institutions both local and regional, supporting locally-appropriate mechanisms for allocating and restricting access, enforcing transparent and incremental penalties to manage trust, and able to revise rules as circumstances change.