In this edited volume, global experts in ecology and evolutionary biology explore how theories in ecology elucidate the invasion processes while also examining how specific invasions informs ecological theory. This reciprocal benefit is highlighted in a number of scales of organization: population, community and biogeographic, while employing example invaders in all major groups of organisms and from a number of regions around the globe. The chapters in this volume utilize many of the cutting edge observational, experimental, analytical and computational methods used in modern ecology. Through merging conceptual ecology and invasion biology we can obtain a better understanding of the invasion process while also developing a better understanding of how ecological systems function.