John Toland was notorious. Condemned by the Middlesex Grand Jury and the Irish parliament for authoring Christianity Not Mysterious (1696), he was to spend much of his career on the heterodox fringes of intellectual life in Britain and beyond. Yet he was also an intimate of a series of influential politicians and played a crucial part in the Hanoverian succession of 1714. A pamphleteer, a polemicist and a prankster of the first order, modern scholarship has struggled to position his writings within the debates of his day. This study is the first to fully recount his remarkable biography, and to situate his writings fully within the controversies that shaped them.