This comprehensive volume provides the scientific basis for assessing the likelihood of gene flow between twenty important crops and their wild relatives. The crops discussed include both major staples and minor crops that are nonetheless critical to food security, including barley, corn, cotton, cowpea, wheat, pearl millet, and rice. Each chapter is devoted to one of the crops and details crop-specific information as well as relevant factors for assessing the probability of gene flow. The crop-specific reviews provide insights into the possible ecological implications of gene escape. For each crop, a full-color world map shows the modeled distributions of crops and wild relatives. These maps offer readers, at a glance, a means of evaluating areas of possible gene flow. The authors classify the areas of overlap into three gene-flow categories with respect to the possibility of genetic exchange. The systematic, unbiased findings provided here will promote well-informed decision making and the conservation of wild relatives of crops. This book is particularly relevant to agriculture in developing countries, where most crop biodiversity is found and where current knowledge on biodiversity conservation is limited. Given the ecological concerns associated with genetically modified crops, this reference is an essential tool for everyone working to feed a growing world population while preserving crop biodiversity.