The looming threat of global warming may be the greatest challenge of the present generation. Confronted by the potential of such a massive worldwide calamity, the average citizen often wonders what he or she can do. In this inspiring and optimistic story of a green revolution in the making, a veteran science and technology journalist shows how the unrelenting efforts of a small band of grassroots activists have discovered ways to make solar a practical retail energy solution. The crucial driver for the adoption of solar energy has not been technology but policy. Focusing on initiatives in Germany, he describes the use of the "feed-in tariff" as the most successful policy mechanism yet invented to spur on widespread deployment of solar energy. Turning to California, the author reviews the efforts of policy wonks to create new schemes to make solar affordable at the municipal level. Pioneers in both tree-hugging Berkeley and golf-playing Palm Desert have united in common cause, and other towns and cities are planning to follow suit. As with other emerging trends, as California goes so goes the rest of the country. Concluding with a positive view of the future, the author describes the creativity of many startups fueled by venture capital. Innovation is being applied to every part of the process, from silicon production to financing and installation. The details may still be uncertain, but there’s no doubt that the solar revolution is underway.