Pope John Paul II was a great defender of truly vulnerable human beings throughout his life, affirming their personhood consistently and powerfully. In John Paul II on the Vulnerable, Jeffrey Tranzillo provides a lucid introduction to John Paul II’s philosophical and theological understanding of the human person. Unlike other writings on the topic, Tranzillo’s explicit aim is to highlight an aspect of John Paul’s work that has been largely neglected until now. He shows convincingly that John Paul’s seminal reflections on the human being as a personal agent progressed over time to include human beings at even the most vulnerable stages of development or decline. With this advance in thought, the pontiff began to declare eloquently that the vulnerable are capable of contributing to and enriching the human community through their activity. An engaging overview of John Paul II’s life, thought, and work introduces the book and provides readers with helpful background material. It shows that John Paul’s interest in, and lofty regard for, the human person is rooted in his strong Catholic faith and in the extraordinary life experiences that he interpreted in its light. Following this is an examination of his principal works on the human person, emphasizing their implications for vulnerable human beings as persons and actors. Tranzillo considers this theme in the light of selected Christological texts of John Paul II and then reflects on John Paul’s portrayal of the vulnerable in his social encyclicals and Evangelium Vitae. A final chapter develops the anthropological underpinnings of John Paul’s thought on the radically vulnerable and their personal agency.