Through a selection of in-depth interviews, survey analysis and Qualitative Comparative Analysis of policy debates in post-industrial democracies, this text examines the impact of gender experts on the policy process, and specifically how the advice and recommendations of gender experts are used by policymakers. It rethinks our understanding of gender expertise and the circumstances and factors that lead to expert success in public policy, and identifies the actors involved in this process. This volume also contributes to scholarly knowledge on gender expertise through the inclusion of an in-depth review of feminist and non-feminist literatures, and develops a conceptualization of gender expertise that can be utilized to drive future research.