Will the next phase of environmental action resemble the WTO protests in Seattle, the UN Kyoto Protocols, or a Think Tank inside the Washington Beltway? Gaia's Wager shows that movements play an important role between political parties and interest groups on the domestic scene and the unruly forces of globalization internationally. Only social movements can catalyze a response to the global environmental threat that has a chance of both capturing imaginations and institutionalizing progress toward environmental sustainability. Above all, Gaia's Wager bets on the confluence of big ideas and social action to yield a more hopeful environmental future.