This book explores in unprecedented detail the theological thinking of John Witherspoon during his often overlooked ministerial career in Scotland. In contrast to the arguments made by other historians, it shows that there was considerable continuity of thought between Witherspoon's Scottish ministry and the second half of his career as one of America's Founding Fathers. The book argues that Witherspoon cannot be properly understood until he is seen as not only engaged with the Enlightenment, but also firmly grounded in the Calvinist tradition of High to Late Orthodoxy, embedded in the transatlantic Evangelical Awakening of the eighteenth century, and frustrated by the state of religion in the Scottish Kirk. Alongside the titles of pastor, president, educator, philosopher, should be a new category: John Witherspoon as Reformed apologist. This is a fresh re-examination of the intellectual formation of one of Scotland's most important churchman from the eighteenth century and one of America's most influential early figures. The volume will be of keen interest to academics working in Religious History, American Religion, Reformed Theology and Calvinism, as well as Scottish and American history more generally.