Martin Luther said of this work: "Next to the Bible and St. Augustine, no book has ever come into my hands from which I have learnt more of God and Christ, and man and all things that are." The reformer published an edition of this work in 1516, and several other editions were released throughout his life. Though John Calvin referred to the book as full of "poison," resulting in a rejection of this work among many Protestants, it has remained a popular text among Lutherans. This volume inspired the popular devotional writing of figures such as Johann Arndt and Johann Gerhard.The text itself comes from an unknown source, but shows several characteristics of a strand of German mysticism which was prominent in the fourteenth-century. This book was likely written by a disciple of the popular preacher John Tauler. Throughout 54 brief chapters, the author describes the nature of sin, salvation, and union with God.