Sexual selection is recognized as being responsible for some of the most extravagant morphologies and behaviors in the natural world, as well as a driver of some of the most rapid evolution. While Charles Darwin’s theory is now a fundamental component of modern evolutionary biology, the impact of genotype-by-environment interactions on sexual selection has thus far received little attention. This book represents the first comprehensive analysis of the role genotype-by-environment interactions play in sexual selection and the potential implications that they have for the evolutionary process. The Editors have identified 13 topics that currently define the field and shed light on the impacts of these interactions on sexual selection. This includes key topics, such as resolving the lek paradox and how genotype-by-environmental interactions can compromise the honesty of sexual signals. The volume also outlines key questions that remain unanswered and provides a comprehensive guide to analyzing genotype-by-environment interactions. The mix of theory, empirical studies, and practical instructions from world leading experts make this book a particularly potent and definitive guide on the topic. It will be of interest to evolutionary biologists, spanning from genomicists to behaviorists. “This is a very timely book, covering a topic that should change the way we think about sexual selection. The contributors are all leaders and the topics should provide guidance to many PhD projects in the years to come. GEI is increasingly shown to be important, and it seems likely that it is critical in species where sexual selection is operating. This book is likely to help revitalize the study of sexual selection.” Professor Allen Moore, The University of Georgia “GEIs fascinate evolutionary biologists, but the unique consequences for sexually selected traits have been neglected - until now. This multi-authored book comprehensively explains key theoretical concepts, handles practical ‘how to’ issues and uses classic case studies to illustrate the value of studying GEIs. It is a must read for everyone interested in sexual selection.” Professor Michael Jennions, The Australian National University