""This book attempts to penetrate the nature of that strange spiritual phenomenon which we call mysticism by comparing the two principal classic types of Eastern and Western mystical experience. By means of this comparison, and by explaining the individual features of one type by those of the other, the nature of mysticism itself becomes gradually more comprehensible."" --From the Foreword Dr. Rudolf Otto, who died in 1937, was one of the most distinguished German theologians of this century. Perhaps his best-known book was Das Heilige, which ran through ten editions in Germany before being published in an English translation in 1924 under the title The Idea of the Holy.