The debate over the Lords Supper had momentous consequences for the Reformation, causing the division of the evangelical movement, influencing the formation of political alliances, and contributing to cultural differences among the Protestant territories of Germany and Switzerland. Karlstadt and the Origins of the Eucharistic Controversy is the first full-length study of the beginning of that debate. Going beyond the traditional focus on Martin Luther and Ulrich Zwingli, it emphasizes the diversity of the sacramentarian challenge to traditional belief in Christs corporeal presence and re-evaluates the significance of Luthers colleague, Andreas Bodenstein von Karlstadt, to the debate. The book describes Luthers earliest criticisms of the mass and the efforts in Wittenberg to reform liturgical praxis to correspond with his ideas. It then looks at pamphlets written by other reformers to show how Luthers understanding of the sacrament was adapted and modified outside of Wittenberg. It shows how Karlstadts eucharistic pamphlets introduced into the public debate several arguments that would become standard Reformed criticisms of the Lutheran position. The book also demonstrates the influence not only of Erasmus but also of John Wyclif and the Hussites for discussions of the sacrament, highlights the role of the reformers of Basel and Strasbourg for developing the Zwinglian understanding of the Lords Supper, and draws attention to the early eucharistic theology of the Silesians Kaspar Schwenckfeld and Valentin Krautwald. The book will become an indispensable guide for readers seeking to understand the issues surrounding the outbreak of the eucharistic controversy in the sixteenth century.