Cover Illustration: Satellite image of Southern California and northern Baja California, on October 26, 2003, when strong winds blowing out of the desert created a lake overturn at the Salton Sea, California’s largest lake, on their way to fan 15 major fires closer to the Pacific Coast. The largest conflagration, the Cedar Fire of San Diego County, was the largest recorded fire in California history. Started as a signal fire by a lost, pot-smoking hunter, Sergio Martinez, it burnt 280,278 acres (1,134 km2) and 2,232 homes, and killed 15 people. The yellowish patches in the Salton Sea were due to reflection of sunlight from gypsum (calcium sulfate) crystals that formed when sulfide-rich bottom waters mixed with oxygen-rich surface waters. The U.S.-Mexico border is shown just south of the Salton Sea. Salton Sea and border fence politics are the subject of half the essays in this issue. MODIS true color image courtesy of NASA.