This book is founded on deep and specialised scholarship, not only on the life and works of John Calvin, but on the fluid and confusing currents of the early Reformation in the towns of south Germany and, especially, Switzerland. It is amazing to find that the burghers of Geneva only declared themselves Protestant, more particularly Lutheran, in 1536, the very year Calvin arrived from France. Geneva had always been rent by bloody factions, but recently the faction fighting for independence from the Duke of Savoy, and the bishops and clergy he appointed from his family and caste, had announced its triumph in this way. Bruce Gordon manages to trace the continuing violent factionalism, ever subject to foreign interference. This is the world into which Calvin brought his utter self-confidence as the voice of God, his own amazing scholarship and his clear and insistent writing and rhetoric skills. He put these, and his incessant networking among the emerging Protestant churches and sympathetic Princes, to the cause of reforming, or rather re-establishing, the Church of Christ, in distinction to the synagogue of Satan led by the Anti-Christ which was the Roman Church. He was in no sense a “reformer” of that church, and he would have no compromise with it, especially any doctrines or activities he considered idolatrous. He had a lot of opposition in Geneva and across the Protestant world, but he finally achieved dominance in Geneva, in large part due to the influx of French refugees. These were granted citizenship in return for money, and eventually took control of the town Council, securing Calvin’s place both in Geneva and in the hearts of French Protestants. More important, perhaps, were the protected foreign communities, including the English one, led by (the Scot) John Knox, among others. They thought the Genevan church a model and, along with Calvin’s Institutes of the Christian religion, his Catechism and methods of worship, preaching and teaching, they wanted to establish this back home in England. Unfortunately, Knox’s books against female rule brought him the undying enmity of Elizabeth, so Anglicanism (related surprisingly to the Reformations of other, equally small, Swiss towns) rather than Calvinism was to triumph in England. Knox had more success in his native Scotland, though a powerful, enduring Calvinist stream was established in the English Church. They were no more likely than Calvin to submit to anything less than the pure Gospel and pure worship, bereft of anything not traceable in Scripture. These are variously known as Puritans, non-Conformists and, recently, Evangelicals, whose influence spread to the American and other colonies. Their conflicts are crucial to the development of Western, eventually democratic, institutions. Bruce Gordon, in his beautiful, clear prose, plausibly shows how all this can be traced to the peculiar character and seminal works of one arresting individual. Whether it provokes admiration (as it obviously does in the book’s author) or not will depend on your own preconceptions. For me, it powerfully explains how such phenomena as Islamic State are possible. You need the politics, of course but you need the clear ideology and organisation and you need the well-instructed, enthusiastic people. A brilliant book!