In his call for the church to go to the margins and the peripheries both geographical and existential Pope Francis has defined a new understanding of the mission of the church. But in doing so, he has reached back to the origins of the church, and revived a long and complex theme in Christian history. In To the Margins, the founder of the San'Egidio community in Rome offers a profound reflection on this theme, tracing the many ways Christians have opted for the marginalized and excluded, from the early ministry of the church, to the program of St. Francis, the Worker Priests in France, and the witness of modern figures like Bl. Charles de Foucauld, Mother Maria Skobtsova, and the work of San'Egidio itself. By understanding the many forms of the "margins" and the "marginalized" in our time, we can understand and pursue the mission of the church today.