Description:This study draws on data from numerous sources that support the paradigm of natural hybridization as an important evolutionary process. The review of these data results in a challenge to the framework used by many evolutionary biologists, which sees the process of natural hybridization as maladaptive because it represents a violation of divergent evolution. In contrast, this book presents evidence of a significant role for natural hybridization in furthering adaptive evolution and evolutionary diversification in both plants and animals.