In 1987, Cambridge University Press published a volume entitled Molecules and Morphology in Evolution: Conflict or Compromise? edited by the esteemed British palaeobiologist Colin Patterson. Since the 1980s, we have witnessed a great deal of incorporation of the tools and data of molecular biology into palaeontological hypothesis building and testing. The degree of integration is substantial enough so as to rule out the rather pejorative subtitle of the 1987 volume, ‘conflict or compromise’. We believe a new designation is appropriate: ‘synergy’. Stated differently, our ability to address major questions in biological history requires the integration of molecular methods and data into the palaeobiologist's toolkit. The antagonism implicit in the notion of ‘conflict or compromise’ is more an artefact of disciplinary boundaries and analytical traditions, and is not firmly rooted in the data of biology. Palaeobiologists today routinely consider data from molecular biology in their research on the shape and antiquity of the tree of life (‘divergence’), and in understanding the genetic and developmental mechanisms behind morphological change (‘mechanisms’).

This book documents aspects of this synergy, focusing on these two general categories: divergence and mechanisms. It derives from the symposium ‘molecular tools in palaeobiology’ that took place during the 2009 meetings of the Society of Vertebrate Paleontology in Bristol, UK. In retrospect, we realize that the ‘vertebrate’ orientation of that conference has resulted in a level of taxonomic focus in this book that excludes many important contributions regarding evolutionary divergence and mechanisms. Nevertheless, this is no small taxonomic category, and there has been much to say about it since 1987.