Teachings for an Unbelieving World is a newly discovered work written by St. John Paul II—then Archbishop Karol Wojtyła of Kraków—in the years just after Vatican II. He uses St. Paul’s sermon to the people of Athens in Acts 17 as a framework for articulating the faith in a culture of skepticism and unbelief. These thirteen brief reflections provide compelling teaching for Catholics in today’s post-Christian world and give fresh insight into JPII’s pontificate. This is the first English-language publication of this important work. St. John Paul II composed these thirteen reflections at a unique point of convergence in history—the closing of Vatican II in 1965 and the 1966 observance of one thousand years of Christianity in Poland. Teachings for an Unbelieving World is an extended meditation on Acts 17 where Paul speaks to the cultural elite of Athens after he observed an altar of an unknown god in the city. Quoting from both the Bible and the documents of Vatican II, John Paul II draws timely wisdom from the apostle’s mission to bring the truth of the Gospel to a worldly culture of sophistication and disbelief, one not unlike our own. The future pope reveals Paul’s memorable encounter as an enduring framework to boldly present the core truths of Catholic faith to those living under Poland’s communist regime. In so doing, JPII demonstrates how relevant Paul’s words are today and equips us to meet the challenges of proclaiming the faith in our times. Teachings for an Unbelieving World affirms the continuity of Catholic faith about: humanity’s place in God’s creation; our search for meaning, truth, and freedom; addressing a culture of unbelief; the gift of redemption in Jesus Christ; the grace of the Holy Spirit; the role of the Church in the world; the power of the Eucharist; the redemptive and self-giving nature of human love; and the importance of prayer.