With the Earth's atmosphere increasingly being used as a convenient sink for myriad pollutants, humanity faces the daunting problem of conserving a vital resource that, like the oceans, outer space, and Antarctica, defies geographical boundary. In this comprehensive look at the atmosphere's deterioration - an issue that has emerged as a leading international concern - Marvin S. Soroos considers how it is being altered and degraded by a rapidly growing and industrializing human population and what is being done to preserve it. In case studies of four international atmospheric agreements - governing atmospheric testing of nuclear weapons, acid precipitation, ozone-layer depletion, and global climate change - Soroos demonstrates the uneven, piecemeal approach that the international community has taken. He draws conclusions regarding the circumstances favoring cooperation among states and ponders the likelihood that governments will pursue environmental security in a preventive, collaborative way rather than by depending on the self-reliant, defensive strategies that have proved so costly and counterproductive in the pursuit of military security.