Book excerpt: 2021 Association of Catholic Publishers third place award in theology 2021 Catholic Media Association Award second place award in theological and philosophical studies 2021 Catholic Media Association Award second place award in future church Globalization is uniting the world more closely than ever before while at the same time increasing the likelihood of division and conflict. Humanity faces problems of an unprecedented scope: vast inequality, climate change threatening the conditions of life on this planet, and a great population migration that includes human trafficking and desperate refugees. What does this global plight demand of a church called to be a sign and instrument of the union of all in God? In this book, Mary Doak shows how the church must rectify its own historic failures to embody the unity-in-diversity it proclaims, especially with regard to women and Jews. Only then, and through responding to the demands of the current global crises, can we learn what it means to be the church—that is, to be a prophetic witness and public agent of the harmony that God desires and the world deeply needs.