In his book, An Introduction to Christian Philosophy, Mr. Spier demonstrated his ability to give a compact exposition of the philosophy of Hermann Dooyeweerd. And now within comparatively few pages, Mr. Spier ex-posits and criticizes Existentialism, a movement noted for its obscurity and verbosity. Mr. Spier's work is of an introductory nature and does not intend to give an exhaustive account. The merit of his clear exposition and criticism is for the reader to judge. -Translator's Preface.