John Calvin (1509-1564) is one of the most important figures in religious history. Sitting on the cusp of the medieval and early modern world, he was centre stage during the Reformation. In this new biography, Michael Mullett introduces us to this most important figure, tying his life together with that of Martin Luther, but also valuing his individual contribution and influence. From what Calvin himself described as 'humble beginnings', he became one of the most influential theologians of the Protestant Reformation. The influence of his teachings and the development of Christian theology into what was to become known as Calvinism, swept across Europe, reinforcing the Reformation's radical break from the Catholic Church. John Calvin was 'a mighty and formidable man, able to achieve the vast amount he did because of his unbending conviction of his rightness'. Michael Mullett explores the significant influences on Calvin and his work, and the relationships that he formed along his reforming path. Looking not only at the impact of Calvin throughout the early modern period and the importance of his work to contemporaries, Michael Mullett also assesses the impact that Calvin's works have had in shaping the modern world, and the relevance that they still have today.