Perhaps the greatest achievement of Teilhard de Chardin, from the Christian viewpoint, is that he presented mankind with a theory of an evolving universe tending toward Christ as its end (""as Omega""). And perhaps the greatest problem that he bequeathed to his disciples is to explain how the evolutionary process, which is a natural one, can attain the Christ-Omega, which is a supernatural end. Professor Baltazar rejects the hitherto most plausible explanation to the effect that the evolutionary process itself must be ""supernatural"" -- i.e., must be a gratuitous gift of God -- as incomplete and satisfying, and applies himself to a different approach to the problem of the supernatural by developing a philosophy of process intrinsic to, and therefore derived from, an evolving universe. The problem essentially is one on which hinges Teilhard's acceptability as ""orthodox"" in the eyes of the Catholic Church, and Baltazar, recognizing the academic importance of the question, brings to it a fresh approach which, whatever its failings from the standpoint of scholastic dialectics, is worthy of note. Although the author's style and treatment are not unduly technical, the specialized nature of his subject will excite interest only among those few who have read and digested enough of Teilhard's work to appreciate the quality of the dilemma involved in his view of the universe.