William Penn (1644-1718) – Quaker activist, theorist of liberty of conscience, and colonial founder and proprietor – played a central role in the movement for religious liberty on both sides of the Atlantic for more than four decades. This volume presents, for the first time, a fully annotated scholarly edition of Penn's political writings over the course of his long public career, tracing his thinking from his early theorisation of religious toleration and liberty of conscience in England, as a leading member of the Society of Friends during the 1670s, to his colonial undertaking in Pennsylvania a decade later, his controversial role in the years leading up to the 1688 Revolution, and the ongoing consequences of that Revolution to his future prospects. Penn's political writings provide an illuminating window into the increasingly sophisticated and influential movement for liberty of conscience in the early modern world.