Jürgen Moltmann is Professor of Theology Emeritus at the University of Tübingen, Germany. Early on in this sagacious work, he answers the question of why there aren't any more grand works of systematic theologies: "The divine promise and the awakened hope teach every theology that it must remain fragmentary and unfinished, because it is the thinking about God of men and women who are on the way and, being still travellers, have not yet arrived home. That is why the medieval cathedrals and ministers also had to remain unfinished, so that they might point beyond themselves."

The author of The Spirit of Life: A Universal Affirmation and many other works sees theology as an adventure of ideas that exercises mind, body, and soul. Moltmann certainly stretches our imagination as he ruminates about the hermeneutics of hope, Latin American liberation theology for the First World, Minjung theology for the ruling classes, feminist theology for men, and the multiple meanings of the Trinity. In the last chapter, this prolific German theologian affirms the importance of wisdom, which he defines as "the ethics of knowledge." For Christians growth in wisdom comes through God's Spirit as a constantly surprising source of renewal.

At one point, Moltmann notes: "All Christians who believe and who think about what they believe are theologians, whether they be young or old, women or men." With great insight the author sheds light on the common tasks of all the religions of the world to secure the survival of humanity and to take care of the earth. Whether writing about the spiritual practices of play or hope, Moltmann proves himself to be an enthusiastic supporter of an active Christian faith always seeking new frontiers.