A new book is still on its trial and the amateur is not in a position to judge it. It has to be tested against the great body of Christian thought down the ages, and all its hidden implications (often unsuspected by the author himself) have to be brought to light. Often it cannot be fully understood without the knowledge of a good many other modern books. If you join at eleven o’clock a conversation which began at eight you will often not see the real bearing of what is said.