Polls and election results show Americans sharply divided on same-sex marriage, and the controversy is unlikely to subside anytime soon. This work provides a roadmap to the ongoing debate. Taking a "point/counterpoint" approach, the authors, one a philosopher and prominent gay advocate, and the other a nationally syndicated columnist and co-founder of the National Organization for Marriage, explore fundamental questions: What is marriage for? Is sexual difference essential to it? Why does the government sanction it? What are the implications of same-sex marriage for children's welfare, for religious freedom, and for our understanding of marriage itself? While the authors disagree on many points, they share the following conviction: Because marriage is a vital public institution, this issue deserves a comprehensive, rigorous, thoughtful debate.