Hybrid zones--geographical areas in which the hybrids of two races are found--have attracted the attention of evolutionary biologists for many years, both because they are windows on the evolutionary process and because the patterns of animals and plant variation seen in hybrid zones do not fit the traditional classification schemes of taxonomists. Hybrid zones provide insights into the nature of the species, the way barriers to gene exchange function, the genetic basis of those barriers, the dynamics of the speciation process. Hybrid Zones and the Evolutionary Process synthesizes the extensive research literature in this field and points to new directions in research. It will be read with interest by evolutionary biologists, geneticists, and biogeographers. "Provides a timely update on many theoretical issues and includes examples of long-term multidisciplinary studies. . . . deserves a wide audience." -- Jack W. Sites, Jr. (Brigham Young University), Science "Provides in-depth background introducing important concepts and analytical methodologies used in hybrid zone studies. Several excellent illustrative case histories are also presented, highlighting many of the most extensively studied hybrid zones....The concepts, methodologies, and diversity of issues stressed in each of the case histories provide valuable reference material for ecologists and evolutionary biologists regardless of taxonomic affinities or research interests." -- Ecology "Presents a masterful overview of hybrid zone theory and empirical evidence on the nature of hybrid zones in a variety of organisms....Each of the case studies was extremely interesting, and went beyond reporting of facts, often providing thoughtful and critical interpretations of the data....Would be useful in the libraries of most evolutionary biologists, as a topic for seminars, and a `must acquisition' for university and museum libraries." -- American Zoologist Richard G. Harrison is at Cornell University.