This compact volume contains a series of lectures given by Dooyeweerd during his lecture tour throughout the United States and Canada in 1959. These lectures express the core essence of Dooyeweerd's four volume philosophical work A New Critique of Theoretical Thought. In a masterful summary, Dooyeweerd first tackles the central dogma of the modern era, namely, the dogma of the autonomy of theoretical thought. While this dogma has been challenged in many ways, both in the twentieth, and twenty-first centuries, none of these challenges have made the dogma a truly critical question. If they had, the claims for the constant centrality of rational thought from the ancient Greeks to medieval Thomastic scholasticism and on to both the modern and post-modern humanist expressions would be exposed as possessing radically different presuppositions which transcend the confines of theoretical thought. By subjecting this dogma to a truly radical critique, Dooyeweerd demonstrates that all theoretical thought is grounded upon religious presuppositions that exceed the boundaries of both philosophy and theology, and which need to be clearly exposed and articulated if theoretical thought is to truly understand its own nature. He similarly demonstrates how such a critique provides the basis for the development of a Christian philosophy that can challenge historicism and establish a fruitful dialogue with non-Christian thought.