Few books in theology have faced the twentieth century with all its horrors and yet revoiced the redemptive Christian antidote as convincingly as Joseph Ratzinger's 1968 masterpiece, Introduction to Christianity. In Gift to Church and World, John Cavadini and Donald Wallenfang present papers from the conference held at the University of Notre Dame to celebrate the fiftieth anniversary of this classic book's publication and, through it, Ratzinger's lasting influence on the world of Christian theology. Bishops, priests, and lay men and women set their hands to 'the trowel of tribute,' honouring the legacy of Joseph Ratzinger and the pivotal role he has played in the recent history of the Catholic Church. Covering Ratzinger's work on fundamental theology, philosophical theology, dogmatic theology, spiritual theology, and pedagogy, the essays gathered here shed new light on Ratzinger's theological genius. Throughout, the authors return to his compelling expression of the divine call to reawaken to our true identity as beloved children of God.  Altogether, readers will deepen their appreciation and understanding of the theological contributions of Joseph Ratzinger, and his continued relevance to mission and evangelisation today.