Habitat fragmentation and global climate change are the two major environmental threats to the persistence of species and ecosystems. The probability of a species surviving such changes is strongly dependent on its ability to track shifts in the environmental, either by moving between patches of habitat or by rapidly adapting to local condition. These 'solutions' to problems posed by environmental change depend on dispersal propensity, motivating our desire to better understand this important behavior. This book is a comprehensive overview of the new developments in the study of dispersal and the state-of-the-art research on the evolution of this trait. The causes, mechanisms, and consequences of dispersal at the individual, population, and species levels are considered. The promise of new techniques and models for studying dispersal, drawn from molecular biology and demography is explored. Perspectives on the study of dispersal are offered from evolution, conservation biology, and genetics. Throughout the book, theoretical approaches are combined with empirical data, and examples are included from as wide a range of species as possible.