Originating in a symposium on 'Vegetation and Flora of La Frontera' held at the American Institute of Biological Sciences to honour the late Forrest Shreve, pioneer desert ecologist, this collaboration of outstanding biologists, environmentalists, and climatologists from both sides of La Frontera presents a new agenda for study of the strikingly diverse shrub and grassland ecosystems of the US/Mexico border. The twenty-two contributors focus their expertise on historic cross-border changes in vegetation stemming from disparate land-use practices in the United States/Mexico border region -- La...