As the major deistic thinker of the decades before and after 1700, John Toland linked biblical criticism, metaphysical speculation, and political pamphleteering in ways that intrigued, enraged, and embarrassed a generation of writers. John Locke, Daniel Defoe, Jonathan Swift, and Gottfried Wilhelm Leibniz felt compelled to respond to his critiques of religious belief. His discussions of John Milton, sectarian toleration, the Protestant Succession, and the status of the Jews and the Irish in Great Britain made him a significant spokesman for Whig causes. His work on Giordano Bruno, the Druids, and exoteric philosophy introduced a distinctive perspective into philosophic exchanges of the period.

Probably the bastard son of an Irish cleric and his concubine, John Toland was born in Londonderry, Ireland, on 30 November 1670. He was christened in the Roman Catholic Church as "Janus Junius" (which he later employed as a pseudonym), but as a schoolboy he was given the...