After volume 33, this book series was replaced by the journal "Evolutionary Biology." Please visit www.springer.com/11692 for further information. This volume is the 33rd in this series, which includes 32 numbered volumes and an unnumbered supplement. Several special volumes have also been published as separate monographs. This volume, like the others in the series, has chapters devoted to a broad spectrum of topics. Indeed, the editors continue to solicit manuscripts on subjects covered by the encompassing rubric of Evolutionary Biology. "Volume 33 continues the grand tradition of Evolutionary Biology in being the most comprehensive series in the field. The chapters are always up-to-date, informative, and stimulating; sometimes infuriating. Just what good scientific literature should be! Particularly attractive is the free-wheeling spirit of the series: no style or length is imposed. If you want to remain cognizant of contemporary evolutionary advances in general and have time to read only one volume a year outside your own specialty, make it Evolutionary Biology." (Jeffrey R. Powell, Ph.D., Yale University)