After volume 33, this book series was replaced by the journal "Evolutionary Biology." Please visit www.springer.com/11692 for further information.

The nature of science is to work on the boundaries between the known and the unknown. These boundaries shift as new methods are developed and as new concepts are elaborated (e.g., the theory of the gene, or more recently, the coalescence framework in population genetics). These tools allow us to address questions that were previously outside the realm of science, and, as a consequence, the boundary...

Evolutionary Biology, of which this is the twenty-second volume, continues to offer its readers a wide range of original articles, reviews, and commentaries on evolution, in the broadest sense of that term. The topics of the reviews range from anthropology, molecular evolution, and paleobiology to principles of systematics. In recent volumes, a broad spectrum of articles have appeared on such subjects as asymmetric sexual isolation, biochemical systematics in plants, species selection, DNA hybridization and phylogenetics, modes of evolution in Pleistocene rodents, and development and...

The first volume of Evolutionary Biology was published twelve years ago. Since that time twelve volumes and one supplement have appeared. As stated in earlier prefaces, we are continuing the focus of this series on critical reviews, commentaries, original papers, and controversies in evolu- tionary biology. It is our aim to publish papers primarily of greater length than normally published by society journals and quarterlies. We therefore invite colleagues to submit chapters that fall within the focus and standards of Evolutionary Biology. Manuscripts should be sent to anyone of the...

It is not often that one has the opportunity to send a public birthday greet ing to a friend and colleague of many years, and to congratulate him on having reached the age of reason. In fact it happens only once, and comes then as a surprise. Surely it was only a few years ago that we sat together at an International Genetics Congress in Ithaca, and only yesterday that we became members of the same department. The eighth floor of Schermerhorn Hall had a north end where the flies were and a south end furnished with mice, and in between, a seminar room and laboratory. There the distances were...