No single word conjures up religion, spirituality or the sacred more than `holiness". Yet its meaning in Christian theology and application in Christian practice, has been greatly misunderstood. Few Quakers today of any persuasion would recognize the mystical depth of meaning the concept had for Quakers down through the centuries. Holiness: The Soul of Quakerism recovers the essential place of holiness theology in three centuries of Quaker history. It explores how Quaker spirituality was shaped in its inception by the experience of union with God, otherwise known in Christian tradition as `perfection" and examines selected figures from Quaker history who represent different emphases of holiness in the context of their time and culture. It examines the history of Quakerism in terms of the holiness tradition arguing that the holiness heritage of Quakerism can be traced to its founder, George Fox, who understood union with God or perfection, as the essence of the Christian experience. The study identifies eight different traditions of Christian holiness and shows how Quakerism uniquely combined elements of each, reinterpreting them into a radical new kind of holiness movement. It also identifies eight essential elements that comprise Quaker holiness and shows how these are located within differing emphases in the writings of early Friends and in Quakerism thereafter—Scripture, eschatology, conversion, evangelism, charisma, suffering, mysticism and perfection.