Crossbills and Conifers explores an intimate natural historical connection, revealing why crossbills have become an exemplar of diversification and coevolution. Craig Benkman takes readers on his 40-year journey of research and discovery, exploring a series of unique and interrelated findings about the behavior, ecology, evolution and conservation of a remarkable group of birds. Key to revealing these insights is the ease with which one can measure how variation in bill structure, and conifer cone structure and phenology, influence the efficiency at which crossbills extract seeds from cones. Consumer-resource interactions are fundamental to much of ecology, but such relationships are rarely so readily quantified, not least with the coevolutionary arms race driving the evolution of the newly discovered Cassia Crossbill. This accessible and handsomely illustrated book will appeal to a wide audience. Students of ornithology and evolutionary biology will gain a greater understanding of the value of natural history and especially the utility of knowing when who eats whom and why. Bird enthusiasts and naturalists will learn much about the world of crossbills, the causes of their diversity which has challenged and inspired many ornithologists, and the threats that these birds face.