Prayer changes things according to the old clich. But what things, and how? Engaging with biblical texts on prayer, Rob Ellis finds valuable guidance on the contents of prayer, as well as evidence of early wrestling with its problems. He also reviews the works of leading historical theologians such as Origen, Augustine, Aquinas, and Calvin before asking how the question Who is God? connects with our thinking about intercession. Concluding with a Trinitarian theology of intercession that draws on the work of Karl Barth, Answering God will be of interest to church ministers, leaders, and students of theology.