The Work
Introduction to Christianity (Einführung in das Christentum) was first published by Kösel-Verlag, Munich, in 1968, based on lectures delivered by Joseph Ratzinger at the University of Tübingen in the summer semester of 1967. It was translated into English by J. R. Foster and published by Herder and Herder (New York) in 1969. The book has never been out of print and has been translated into more than seventeen languages. A revised edition with a new preface was issued in 2000, adding Ratzinger's reflections on developments since the original publication.
The book was written at a particular moment of cultural and theological crisis: the late 1960s, when the Western university world was convulsed by the student revolution of 1968, and when the Catholic Church was absorbing the upheavals of the Second Vatican Council (1962-65). Ratzinger had been one of the most progressive theological voices at Vatican II; by 1968, troubled by what he regarded as a misreading of the Council in the direction of secular accommodation, he was beginning the shift that would eventually lead him to become the Church's chief doctrinal guardian as prefect of the Congregation for the Doctrine of the Faith (1981-2005) and ultimately Pope Benedict XVI (2005-2013).
Biblical Engagement
The book is structured as a commentary on the Apostles' Creed, and its biblical engagement is woven throughout rather than concentrated in particular passages.
Matthew 16:16 - Peter's confession, 'Thou art the Christ, the Son of the living God' - is the book's starting point for reflection on what Christian faith means as personal confession. Ratzinger argues that belief in Jesus as the Christ is not primarily an intellectual assent to propositions but a personal relationship of trust (Vertrauen) that transforms the one who makes it. The Creed is not a doctrinal checklist but a grammar of encounter.
John 20:29 - 'Blessed are those who have not seen and yet have believed' - is central to Ratzinger's phenomenology of faith. He uses the figure of the doubting Thomas, who moves from sight to faith, to argue that Christian faith is always mediated through the testimony of others (the community of witnesses) and is never a direct, unmediated vision. This makes Christian faith permanently vulnerable to doubt - but also permanently supported by the community of those who have gone before.
John 1:14 - 'And the Word became flesh and dwelt among us' - anchors the book's Christology. Ratzinger's central argument about the Incarnation is that the Christian claim is not that God's logos (reason, word, meaning) is an abstraction available to unaided human reason, but that the logos has become a particular human being in a particular historical time and place. This particularity - Jesus of Nazareth - is the scandal and the hope of Christian faith: it means that meaning is not a philosophical discovery but a personal encounter.
1 Corinthians 15:17 - 'if Christ has not been raised, your faith is futile and you are still in your sins' - grounds Ratzinger's insistence on the bodily resurrection as the non-negotiable center of Christian hope. Against interpretations that reduce the resurrection to a spiritual experience or a metaphor for Easter faith, he insists on the historical reality of the event as the foundation of everything else.
Author and Context
Joseph Aloisius Ratzinger was born in Marktl am Inn, Bavaria, on April 16, 1927. He was ordained a priest in 1951 along with his brother Georg. He earned his doctorate from the Ludwig Maximilian University of Munich in 1953 and his habilitation in 1957. He was appointed Professor of Fundamental Theology at Bonn in 1959, Münster in 1963, and Tübingen in 1966, where he taught when the Tübingen lectures that became this book were delivered.
Ratzinger's theological formation was deeply shaped by Augustine and Bonaventure (his two doctoral mentors), by Hans Urs von Balthasar's ressourcement theology, and by his experience of the Second World War and its aftermath. The 1968 lectures were delivered just weeks before the May student revolt convulsed Tübingen, an experience that Ratzinger later described as formative in his conviction that theology must remain anchored in the Church's tradition rather than accommodate itself to every cultural moment.
Structure and Argument
The book opens with a masterful chapter on the nature of belief, using a parable by Søren Kierkegaard about a clown attempting to warn a town of an approaching fire - but being laughed at because he looks like a clown - to illustrate the theologian's predicament: speaking truth in a form that the culture cannot take seriously. Ratzinger then examines the relationship between doubt and faith, arguing that the modern person who believes always believes against the pressure of doubt, and that this is not a deficiency in faith but its authentic form.
Part I addresses what it means to believe today, engaging the secular critique of religion from Freud, Marx, and the Enlightenment. Part II, the book's longest section, expounds each article of the Apostles' Creed: God the Father, Jesus Christ (with extensive Christological reflection), the Holy Spirit, the Church, the resurrection of the body, and eternal life. Part III is brief, focusing on the Incarnation as the summit of the Creed.
The Christological section is the theological heart of the book. Ratzinger argues that the 'titles' given to Jesus in the New Testament - Christ, Son of God, Lord, Word - are not mythological accretions but the disciples' attempt to describe an experience that exceeded their existing categories. The Chalcedonian definition of two natures in one person is not a Greek distortion of a simple Jewish message but the most precise available formulation of what the disciples encountered.
Critical Reception
The book received immediate acclaim as the finest theological introduction to Christianity written for the educated secular audience since C.S. Lewis's Mere Christianity (1952). It was widely assigned in Catholic and Protestant theology courses. Liberal theologians appreciated its engagement with the secular critique of religion; conservative theologians appreciated its firm defense of orthodox Christology. Hans Küng, who was then Ratzinger's colleague at Tübingen, praised it; their subsequent theological divergence makes this early convergence historically interesting.
Reviewers particularly noted the book's combination of philosophical sophistication (Ratzinger engages Descartes, Kant, Hegel, and Heidegger fluently) with devotional warmth and theological precision. The opening meditation on doubt and belief was singled out as one of the most honest accounts of the phenomenology of faith in modern Catholic theology.
Theological Significance
The book's chief theological contribution is its account of faith as a form of trust (Vertrauen) that is never without the risk of doubt - the 'negative' possibility that keeps faith honest and prevents it from collapsing into either naive credulity or arrogant certainty. Ratzinger's phrase 'the courage to believe' (der Mut des Glaubens) captures this: in a secular age, Christian faith requires genuine courage, not the comfortable assumption that everyone agrees.
The Christological section anticipated several themes that would dominate New Testament scholarship in subsequent decades: the importance of the titles of Jesus, the relationship between the historical Jesus and the Christ of faith, and the coherence of Chalcedonian Christology with the biblical witness. Ratzinger's formulation - that the Creed does not add doctrinal freight to a simpler Gospel but gives precise form to what the Gospel already claims - has been widely influential.
Legacy
The book established Ratzinger as the most intellectually distinguished Catholic theologian of his generation. Its influence on Catholic theological education over the subsequent fifty years has been enormous. When he became Pope Benedict XVI, the book was reissued and widely distributed, introducing a new generation to his theological vision. His two-volume Jesus of Nazareth (2007, 2011) can be read as the mature complement to this early work: where Introduction to Christianity addresses the systematic question of what it means to confess the Creed, Jesus of Nazareth addresses the historical and exegetical question of who the Jesus of the Gospels is.
Reading Alongside Scripture
Readers should study the Apostles' Creed alongside the key biblical passages that ground each article: Matthew 16:13-20 (Peter's confession), John 1:1-18 (the prologue to the Gospel of John), 1 Corinthians 15:1-58 (the resurrection chapter), Acts 2:14-36 (Peter's Pentecost sermon), and John 20:24-29 (Thomas and the risen Christ). Augustine's Confessions provides the theological and spiritual framework within which Ratzinger is operating.
Further Reading
- Pope Benedict XVI (Joseph Ratzinger), Jesus of Nazareth, 2 vols. (2007, 2011) - the mature companion to Introduction to Christianity, applying its Christological vision to the Gospel texts in detail. - Aidan Nichols, OP, The Theology of Joseph Ratzinger: An Introductory Study (1988) - the most thorough scholarly analysis of Ratzinger's theology as a whole, placing Introduction to Christianity within his broader intellectual development. - Tracey Rowland, Ratzinger's Faith: The Theology of Pope Benedict XVI (2008) - a more recent and accessible introduction, drawing on the full range of his writings.