This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book focuses on the UK, Australia and the US because they highlight the clash of values between governments and diverse groups which strongly oppose or favour marriage. It undertakes elements of a 'most similar system' approach for the purposes of analysis, focusing on values as the independent variable to understand how the policies in each country have shaped the institution of marriage. The book identifies not only the governments' values, but also those of other relevant political actors and reflects on their demands and influence over marriage policies. It addresses the ongoing debate about which comes first—marriage or social and economic wellbeing. The book also considers different political frameworks of values and their applicability and furthermore seeks to understand and identify strengths and weaknesses in the policy-related uses of core political convictions.