Food webs are one of the most useful, and challenging, objects of study in ecology. These networks of predator-prey interactions, conjured in Darwin's image of a "tangled bank," provide a paradigmatic example of complex adaptive systems. This book is based on a February 2004 Santa Fe Institute workshop. Its authors treat the ecology of predator-prey interactions, food web theory, structure and dynamics. The book explores the boundaries of what is known of the relationship between structure and dynamics in ecological networks and will define directions for future developments in this field.