This is first book-length synthesis of the natural history, ecology, and conservation of the seasonally wet pools that occur throughout the formerly glaciated region of eastern North America -- essentially the Great Lakes Basin, New England, and adjacent areas of Canada and the United States. Introductory chapters define vernal pools; provide overviews of their formation and physical-chemical-hydrological characteristics; and present data critical for assessing, regulating, and managing pool ecosystems. The chapters that immediately follow the introduction explore the biology of microscopic life forms such as bacteria, algae, and fungi and the great variety of higher plants associated with vernal pools. The next chapters delve into the descriptions, distributions, habitat requirements and life-history strategies of pool animals, and the ecological processes and patterns associated with the composition and dynamics of pool communities over time. A final chapter discusses research needs and conservation considerations that are a part of the ongoing effort to recognize, understand, protect, and manage vernal pools as viable elements in the landscape of eastern North America. An extensive appendix identifies all animals that have been reported from vernal pools of the region and describes their habitat requirements, geographic distribution, and life history characteristics. Technical terms related to vernal pools are defined in a glossary. An extensive bibliography contains a vast listing of published literature, websites, and unpublished reports.