In 2015 the Supreme Court made history by ruling that the constitution protects the right of same-sex couples to get married. The third edition of perhaps the most influential book on the subject explains the Court's reasoning and what the consequences of the decision have been. The book also explains why the Supreme Court declined to rule that a ban on same-sex marriage was irrational or hateful or that the ban was an indirect form of gender discrimination. Instead, the Court ruled that there is a fundamental constitutional right to marry that covers same-sex couples. The book discusses the dissent's claims that the decision will lead to constitutional protection for polygamy. It also covers the controversy over whether there should be special laws that allow religious business owners not to serve same-sex couples who are married. This book is free of jargon and is accessible to anyone interested in same-sex equality, the Supreme Court or constitutional law generally.