Savannas and barrens were major components of the historic North American landscape before it was extensively altered by agricultural and urban development during the past century. Rock outcrop plant communities and serpentine barrens are of interest because they are refuges for endemic species adapted to extreme environmental conditions. Many of these communities are currently reduced to less than one percent of their original area and are imperiled ecosystems. This book provides a coherent and readable summary of the technical information available on savannas, barrens, and rock outcrop plant communities. It is organized by region, into four parts: eastern/southeastern region, central/midwest region, western/southwestern region, and northern region. Written by internationally recognized regional specialists, each chapter includes a description of the climate, geology, and soils associated with the community, and information about its historic and current vegetation. This book will be a useful text for graduate and advanced undergraduate students studying vegetation ecology, as well as a valuable reference for professional and amateur naturalists interested in the conservation, restoration, and management of these communities.