This is the first major archivally-based study of the political career of Wenzel Anton Kaunitz, State Chancellor of the Habsburg Monarchy from 1753 to 1792. Author of the diplomatic revolution of 1756 and a brilliant foreign minister of the Austrian Empire, Kaunitz was virtually the third head of state under Maria Theresia and Joseph II. He emerges from this study as the key figure in the development of enlightened absolutism in the Habsburg monarchy and the guiding spirit behind the modernization of the state.