This is the first full-length biography of the man who, through a combination of industry and intellect, became one of the central figures in British politics from 1782 to 1817. Based on an extensive range of manuscript sources, the book follows Lord Grenville's stunning personal and political career as he rose in trun from Irish Secretary to Speaker of the House of Commons, Home Secretary, Foreign Secretary, Prime Minister and finally, Opposition leader from 1807 until his retirement from party politics in 1817. Lord Grenville's outstanding political achievements during these years were many. He played a vital supportive role to his cousin, the younger Pitt, from 1783 to 1791; he was the main author of the Renunciation Act of 1783 and the Canada Act of 1791, and was a major contributor to other specific measures, including the Union of Ireland; his views on foreign affairs decidedly shaped government policy. This engrossing study illuminates Grenville's pervasive influence not only during his 35-year career but in the subsequent course of British history.