The author of this work, in dealing with major aspects of William Ockham's thoughts, argues that what underlies Ockham's intellectual as well as religious understanding, and what it points to is his high view of human capability. Especially significant is the role of reason in the formation of religious doctrines as universal truths. By examining Ockham's original writings and major contemporary scholarship, the author knits together the seemingly isolated topics to present a unified picture of a medieval mind which had made enormous contribution to the history of human ideas and religious habits. Although Ockham's high view on human capability had been suggested, no comprehensive research was undertaken to establish the theory and indicate its implication. The work is timely, considering the fact that human capability which is not void on the dimension of spirituality is important for safeguarding religious pursuit from neglecting both rational and volitional responsibilities. The significance of the justified relation between human contribution and divine will which dominates the discussion of this book is as titillating as the more ancient debate about the relation between divine grace and human volition.