It's difficult to classify this book, but you could describe it as multiple responses from Thielicke to the question of the relevance of Christian belief in the world. About half the book deals with the growing interest in Marxism as an alternative worldview. Thielecke addresses this by showing that Marxism's anthropology is reductionistic to one's material contributions in the world and that it lacks the understanding of the spirit of man and where God places humanity. The book does jump around a bit in thought and theme since this is a collection of different thoughts of the author.