The Mediterranean Basin, California, Chile, the western Cape of South Africa and southern Australia share a Mediterranean climate characterized by cool wet winters and hot dry summers. These five regions have differing patterns of human settlement but similarities in natural vegetation and some faunal assemblages. The similarities are being enhanced by an increasing level of biotic exchange between the regions as time passes since European settlement in each region. This unique documentation of the introduced floras and faunas in these five regions of Mediterranean climate both increases our understanding of the ecology of biological invasions, and points the way to more effective management of the biota of these regions. This book is an initiative of a subcommittee of SCOPE (Scientific Committee on Problems of the Environment) which realized that the integrity of many natural ecosystems was being threatened by the ingress of invasive species.