Few think of Martin Luther as a theologian of holiness. "Be a sinner and sin boldly," after all - and leave sanctification for Catholics, Orthodox, Finnns and the Reformed. On the basis of close work in the sources, Renovatio advances a revisionist thesis: from the first inklings of his "Augustinian turn" c. 1514 to this death, Luther believed, taught and confessed a robust theology of renewal in holiness. The new, Reformation theology of God's promise (c. 1518) involved significant adjustments in Luther's understanding of justification, but did not alter his commitment to the real renovation of the faithful. Hence the mature Luther's irreducibly trinitarian dogmatics of sin, grace and holiness is "Augustinian" and "evangelical" in equal parts. As such, it commands the regard of theologians who practice their art within traditions stemming from the church's doctor gratiae under the magisterial rule of the gospel --