This book presents the main teachings of Edward Schillebeeckx, widely considered one of the most important Catholic thinkers of the twentieth century. Schillebeeckx is known for his radical departure from traditional theology, which he saw as no longer relevant to the modern world. Because today's world has been shaped by a process of secularization heavily based on reason and progress in science, technology, economics, urbanism, etc., modern people seek relevant answers to their deep existential questions that can be explained rationally. In his quest to foster relevant and meaningful answers for today's world, Schillebeeckx changed the traditional metaphysical content of Christian theology into explanations that radically reinterpret traditional Christian doctrines. Primarily, the supernatural essence of Christianity is given up as irrelevant and is replaced by a natural perspective on the world. In Schillebeeckx's thoroughly historical and truly immanent theology, God is man's terrestrial future; Christ the symbol of universal human values; and the Church is identified with the world as those communities which share these universal human values. Schillebeeckx is convinced that these explanations--emptied of metaphysical content--can help today's people understand their existence in a new, relevant, and meaningful way.