This paper surveys and evaluates the contribution of Jules Isaac to the reorientation of relations between Christians and Jews. Jules Isaac, French educator, historian and bureaucrat committed his life to the repair of relations between Christians and Jews. He played a pivotal role in promoting consideration of Jews and Judaism at the Second Vatican Council. His life and career, while little known or appreciated by religious educators in the English-speaking world, reveal how an agile application of committed diplomacy, critical intellectual endeavour and cooperation across religious boundaries contributed to an increase in Christian self-understanding and a revitalised approach to interreligious relations. The work of religious educators is indebted to the life and career of Jules Isaac.