Recent discoveries from ice-core and marine sediments suggest that global climate systems can change from glacial to near-interglacial temperatures within decades. In order to explain this phenomenon, the authors (all affiliated with the Department of Geological Sciences, U. of California) advance a hypothesis that suggests that the massive energy needed for these changes came for the release of "frozen" methane hydrates (clathrates) stored in marine sediments on continental margins. They argue that the release of the methane caused feedback processes that would explain the surprisingly rapid changes. Annotation c. Book News, Inc., Portland, OR (booknews.com)