There are mounting concerns that the management of our natural global heritage is failing to arrest the rapid extinction of enormous numbers of "specialized" species, especially in the tropics. This book is about specialization and generalization in the use of resources and habitats. The author employs a broad ecological perspective to address three main questions: how ecologists study variation in resource and habitat use and what we learn from these studies; how well existing theory accounts for observations and what the common threads among disciplines are; and finally, what the relationship between resource and habitat use is. This is the first book to provide a comprehensive analysis of ecological versatility and as such, will be of great interest to students and researchers in ecology and environmental biology.