This is an introduction to Karl Barth's ground breaking commentary on St Paul's letters to the Romans from 1922 which laid the foundation to his later theology. Without any doubt Karl Barth was the most influential Protestant theologian of the 20th century. It was his commentary on Paul's Epistle to the Romans that was to gain Barth's international reputation, long before the massive work of his Church Dogmatics. Barth's The Epistle to the Romans is a landmark of twentieth-century theological literature and still required reading for students of the history of modern Christian theology. It is also famously provocative and controversial. Its first appearance helped trigger a parting of ways between Protestant liberalism and the theology of crisis. Today, nearly a century later, it continues to generate widespread discussion among theologians, biblical scholars, and philosophers. This introduction to the text is the ideal companion to study, offering guidance on the theological and historical context, key themes, reception and influence.