Roger Butlin is Professor of Evolutionary Biology, Animal and Plant Sciences, at the University of Sheffield. He has held a prestigious Royal Society Research Fellowship at the University of Cardiff and his work has been recognized by honorary fellowships at the Natural History Museum, Zoological Society of London and Royal Belgian Academy of Natural Sciences. Jon Bridle is a Lecturer in Biology, School of Biological Sciences, at the University of Bristol. Since completing his PhD in Evolutionary Genetics in 1998, he has conducted postdoctoral research in quantitative genetics and evolutionary biology at UCL, University of Cardiff, and Universidad Autonoma de Madrid. He was awarded a fellowship at the Zoological Society of London in 2002. Dolph Schluter is Professor and Canada Research Chair, Biodiversity Research Centre and Zoology Department, at the University of British Columbia. He is a former President of the Society for the Study of Evolution and recipient of the Sewall Wright Award from the American Society of Naturalists. He is a Fellow of the Royal Society of London and of Canada.