Book excerpt: Karl Barth was, without doubt, one of the most significant religious thinkers of modern times. His radical affirmation of the revealed truth of Christianity changed the course of Christian theology in the twentieth century and is a source of inspiration for countless believers. Pope Pius XII declared that there had been nothing like Karl Barth's later thought since Thomas Aquinas. God Here and Now offers a succinct and accessible overview of that thought. In it, Barth outlines his position on the fundamental tenets of Christian belief, from the decision of faith to the authority of the Bible, and from the interpretation of grace to the significance of Jesus Christ. In this way Barth challenges each and every reader to discover what it means to encounter God, here and now.