With this comprehensive study, the author presents an important contribution to research into the theological enlightenment in Germany, with particular reference to neology. He examines the biographies and theology of the two Court Preachers Sack against the background of the controversies surrounding Christianity (vs. La Mettrie), the Eucharist (vs. E. C. Koch; controversy about C. A. Heumann), tolerance (vs. J. M. Goeze), heterodoxy (vs. C. F. Bahrdt), orthodoxy (vs. J. C. Wöllner), Spinozism (vs. Schleiermacher) and the union of Lutherans and Reformed Protestants.